GUIDE TO THE GEOLOGY OF UNION SPRINGS

Elementary Natural History Series; No. 3

BY: Gilbert Dennison Harris

1905 Harris Publishing Co., Cornell University, Ithaca, NY USA

THE ARRIVAL

Your first inpression upon approaching Union Springs will doubtless be that here surely there can be no "natural wonders"; the moderate relief of the land bespeaks even a lack of waterfalls, deep chasms, or lofty view points, objects that are generally conceded to be of interest, though they may fall short of the truly wonderful. But land surfaces, like human faces, are not always to be passed by as uninteresting because they are plain. Before you have seen half what there is here to see, night has come upon you, and much must be deferred to subsequent visits. Let's away to the fields!

CONSULT THE MAP

Europeans say that the American can be picked out on the streets of London, Paris, Berlin, or where not, by the fact that he carries his Baedeker's guide and maps where he can and does consult them frequently. We reply that we are glad that the strangers too shiftless to provide themselves with the ready means of telling where they are and where they are going, are not regarded as our fellow citizens.

In order to understand the geology of Union Springs and vicinity one must know exactly where he collects each specimen and makes each note.

It will be well to head each paragraph of notes, and label each package of specimens with the numerals printed on the map designating where outcrops can be found. Consult the map frequently.

HOW AND WHERE TO BEGIN

Those accustomed to stratigraphic work will know the full meaning of the sections given herewith as Plate II, and will see in advance the general plan of a judicious campaign in this region. However, all will agree that no better way of studying the different horizons represented, can be proposed than beginning at the lowest, first deposited, and taking each subsequent deposit in its proper turn.

IMPORTANT LOCALITIES

CAYUGA JUNCTION

Begin then at the north bank of the railroad cut east of the Junction, or in the stream bed to the south of the railroad. Rocks are here exposed; of a generally light hue, steel-gray to (lust colored; evidently limestones, containing a considerable amount of impurities. In section 4 of Plate 2 a general idea is given of the thickness and appearance of all the rocks exposed at this locality. Note the occurrence of Eurypterous and Leperditia. Turn to Plate 10 to see what man- of animals these names are applied to. Leperditia is a true Crustacean related to the modern Cythere, while Eurypterous belongs to the class ACERATA and has for a modern representative the common horse-shoe crab of our East coast. Rarely indeed are specimens approaching completeness found of Eurypterus (E. remipes). Lucky is the fossil hunter who finds a "head" (cephalothorax) and a few abdominal segments while visiting this locality for the first time.

Take note that the uppermost beds in this vicinity are of thick, more or less banded limestone, and as they pass from view under glacial detritus toward the highway, slope (or dip) slightly southward. Many will see without having their attention called to the fact, that stylolitic structure is common in these rocks.

While passing eastward along the railroad attention should be given to the rolling plain to the south, and observations made on the peculiar, shallow, waterless depressions or sinks that are here to be seen at frequent intervals.

Cross Roads

Just across the road from the old water mill, a large cool spring gushes out to join Sawyer Creek. The size of this spring leads us to suspect limestone rocks in this vicinitv also. Back of the old mill such rocks are seen and their resemblance to those at Cayuga junction is obvious. Notice the southerly dip, and see how far up the stream the rocks may be traced. (See Sect. 5, Plate 2 , base of section. 5", Plate I)

The cut along the railroad at this station is made up of glacial clay with huge, striated boulders.

At Thompson's old gypsum quarry a new type of rock is exposed. It appears black and crystalline, and is indicated in Section 5, Plate 2, by the dark shading. (See also Pl. I, 5'.) Above the gypsum there are, as indicated by the section, several feet of gray limestone, and then at the very uppermost edge there is a thick, peculiar-looking limestone stratum that we shall see more of on Frontenac Island. But, the light colored limestones are of interest because they hold a very different fauna from that already seen near the junction. Notice the small flattened Spirifers and the Lingula apparently without any thickness at all. These are figured on Plate II, along with other species. The peculiar limestone stratum mentioned above may be traced in a south-easterly direction to near the banks of Sawyer Sawyer Creek, across the highway and then to the east-west stretch of the creek behind the buildings south- of the road. Notice the south-easterly dip.

Up Sawyer Creek

To make a trip up this Creek from the road is no easy task, especially in bad weather. But if one succeeds in going some 1/2 to 3/4 mile up stream, he sees beds of drab or buff colored, impure limestones of the Rondout substage, followed by thicker, more bluish beds of typical Manlius. A keen lookout must be kept for the parting line between the Manlius and Onondaga, i. e. the last representative of the Siluric and the first of the Devonic in this particular section. (See Pl. 1,5)

Note how the upper manlius beds contain Stropheodonta varistriata, Spirifer vanuxemi and Crinoid fragments in abundance

At the top of the Manlius, or base of the Onondaga limestone sandy iron pebbles are often met with, indicating the place of the Oriskany sandstone. Note how the Onondaga limestone is more or less dislocated; and, bow it differs materially in color, texture and animal remains from any of the beds heretofore seen. In the pasture lot just below the barn, fine specimens of these various rocks may be found loose and practice may here be had in distinguishing by lithologic characters or fossil remains, rocks of various stages not in situ.

Yawger's Woods

Going westerly across the road, the wooded patches met with indicate outcrops of various limestones and sometimes of Oriskany sandstone. But the really good Oriskany outcrop is not seen till Yawger's woods is reached. The illustration given herewith (Pl.10) shows a little more than 4 f ft of Oriskany sandstone above and perhaps 3 ft. of thin-bedded Manlius limestone below. Even in this small illustration the cavities in the Oriskany sandstone, formed by the taking away of the calcareous shells by percolating waters, are quite conspicuius. Here the geologist must lay in a good supply of fossils; for they are easily obtained, are large and easily determined by Pl's 12-14 of this work. Spirifer arenosus may be recognized by various imprints. Of the two valves you may find the mould or cast of the outside or inside, hence four quite different appearances are produced by one fossil species. Hipparionyx proximus is noteworthy for the fact that the flat valve (pedical valve) is that which in most brachiopods is the larger, while the brachial valve, as shown by fig. 2, Pl. 12 is very rotund or corpulent, especially in old age. Rensselaeria ovoides is much harder to find, especially in nearly perfect specimens. Beaks of this species as shown on Plate 14 are not so rare, but they give a poor idea of the true form of the fossil. A second Spirifer (S. arrectus is 'now and then met with. It is smaller, with fewer and much coarser ribs than in S. arenosus. Chonostropia complanata is fairly common. Rare it is, however, to find the spines along the straight hinge line preserved. See fig. 4, Pl. 12. Meristella is well represent- as Pl. 13 indicates. So much for the Brachiopods.

There are true Mollusks, both bi- and uni-valve. Of the former, a large Megambonia, or fragments of it are now and then broken out. Curved, or loosely coiled inivalves like Plat- and Cyrtolites are not rare here. A few coral fragments are found now and then, but we have yet to find our first trilobite. Above the sandstone, in the woods, Onondaga limestone ledges crop out; below, as we have already seen, are the evenbedded Manlius beds. Compare carefully samples of the two limestones.

Farther on, south-westward by the next field fence, an old quarry shows a more fossiliferous phase of the Manlius. Note the Stromatopora, Spirifer vanuxemi and Leperdita alta.

Still farther on, to the south-west in the bed of the brook, across the road from the old Yawger brick house, practically the same section occurs that we have described on Sawyer Creek. No Oriskany sandstone is present, and the beginning student may test his skill in limestone differentiation at this place. Exactly where is the dividing line between Manlius and Onondaga?

Nearly west of Yawger's woods in the meadow below perhaps 1/4 mile distant is a small old quarry represented in Pl. 2 (lower part of the Plate). It is about 70 feet below the Oriskany sandstone and shows practically the same rocks that we observed above the gypsum at Thompson's quarry on the railroad track, i.e. Cobleskill limestone at top overlain by soil, underlain by drab limestone beds. Continuing westerly across the road and through the fields to a little wooded elevation, another Cobleskill section may be seen. Three or four feet above the Stromatopora-bearing Cobleskill, appear heavy layers usually referred to the Rondout, but here fortunately containing many fossils, though mostly of two species, i.e. Orthothetes interstriatus and Whitfieldella sulcata. Notice the many small lime sinks immediately north and west of this outcrop: the gypsum beds can be but a few feet below the soil.

Going still nearer the lake, across the main highway to the Plaster Quarries, we see how in this region the soft gypsum rocks are thickly mantled with glacial debris Below, the gypsum appears, and extends far beneath water level. From here on west to the lake, gypsum has been quarried for plaster for nearly 100 years.

An old quarry between the railroad track and the lake is shown by Pl. 4. Fishes are abundant in these old ponds, as the keen observer will quickly find out.

Hibiscus Point stands out so prominently that one might think it supported at the water's edge by a solid rock basis. Such is not the case, for many are the times that we have struck the remnant boulders from the boulder clay out some distance from the point. Note the almost perfect smoothness of the bottom, or floor, of the bay south of the point. The bay seems to be due to the wearing eastward, by wave action, of the shore line between the bouldery Hibiscus and the rocky Howland Pt..

Frontenac Island

Frontenac Island is a very noticeable little patch of land and its geology is interesting. You will see there layers of rock between 2 and 3 ft. thick each; in some Stromatoporae are very abundant; in others, other fossils are common. Of the 30 species known from this island, perhaps none strike the collector as more interesting than the abundant bivalve shell, Ilionia sinuata. The white, thin lime lavers of the shell show strongly in contrast with the dark background of the enclosing limestone This is the best collecting ground for Cobleskill fossils in this part of the State. The rocks dip a little to the south but there must be a northern dip between the island and the mainland, for there the Cobleskill beds are again found with a southern dip, this time also showing fine glacial striae. It is very evident that the island owes its existence to synclinal structure here postulated. For the softer Rondout beds immediately upon the hard Cobleskill have been washed away by westerly waves, while portions of the harder Cobleskill lavers have successfully resisted such action.

A few more words as to the organic remains one may obtain here. Mention has already been made of the abundant Stromatopora concentrica. Doubtless a query will arise in many minds relative to the position of this peculiar looking organism in the biologic scale. Indeed no one feels entirely satisfied on this point. But the layers of calcareous encrustations: were produced by little polyps and in some instances more or less structure is still preserved in the indurated mass. But instead of being coral polyps these were presumably of the class Hydrozoa, a class containing but comparatively few rock making species. The Brachiopods of fairly common oc- occurence here are Chonetes jerseyensis, Stropheodonta bipartitia and Rhynchonella pisum. The bivalve Ilionia sinuata has already been referred to and its general appearance is shown oil Plate II.

Union Springs

As you go along the principal street of Union Springs, past hotels and Post Office you little suspect that within a few yards of your walk there is a splendid rock exposure. In the early days, in the historic "40's", One of our State Geologists, Vanuxeum by name, saw this fine outcrop; nor was its discovery then at all difficult, for the modern improvements as you will presently see have almost hidden from view, what then must have been in decided evidence.

On the map you observe that "Tunnel Creek" seems to stop short of the principal street of the village. In reality the water is carried beneath the street in an artificial channel or tunnel. and reappearing, forms the stream and pond lake-wards from the point of disappearance.

If you are at the Post Office and look a little north of east across a green lawn, you notice the gable of a barn adjacent to a somewhat pretentious house. A road leads up to the barn, and as it enters the shady evergreens, you notice the gurgle and rushing of swift-flowing waters. Here is the upper end of the tunnel. From here winding along upwards for several hundred feet you find the moist, cool-faced limestone ledges.

You wonder why you have plodded wearily through muddy plowed fields and brambly pastures to see what of the upper Siluric, Sawyer Creek affords, when here, right in the very heart of the town, so near the station, most every thing is so much better shown. There are, however many things to be learned at each place. The one may be regarded as a supplement and review of the other.

A carefully measured section of these exposures runs as folows:

Section in Union Springs by the Sanitarium.

Ft. Thick Total
1. Onondaga limestone .8 ft. thick, 'with large corals; composed of light, coarsely crystalline CaC03. Lowermost portion stained red with iron oxide and containing sand and clay iron-stones of Oriskanyage 0.80.8
2. Limestone in places replete with Stromatopora2.33.1
3. Dove colored limestone with conchoidal fracture, apparently nonfossiliferous 2.35.4
4. Blue-gray even bedded limestone 2.98.3
5. Stromatopora limestone (See Plate 7) 4.312.6
6. Dark, heavy-bedded blue limestone, with Strohpheodonta and Sp. vanuxemi 6.819.4
7 Alternating beds of grayish and bluish limestone; beds with many fractures; often (dark, cherty, breaking with conchoidal fracture. Sp. vanuxemi, varistriata 9.8 29.2
8. Limestone, dark at bottom, gray at top, weathering lighter. Contains a few Sp. vanuxemi Opposite 4th barn in ravine 1.8 31.0
9. Dark grayish-blue limestone in broken beds; somewhat obscured by detritus 5.2 36.2
10. Dark, bluish gray solid limestone, containing a few Sp. vanuxemi and forming rapids just below 3rd barn. Upper surface rough 1.838.0
11. Even bedded limestone, some lavers 1 ft. thick 4.042.0
12. Light and dark lavers, shaly 0.642.6
13. Light gray or buff colored limestone. Layers 0.05 to 0.08 feet in thickness. Shows stylolitic structure2.344.9
14. Light gray or drab limestone; forming falls near 2nd barn. Contains yellowish clay nodules 3.248.1
15. Very light grayish-brown limestone. Notice dip, about 1-10 N.W 4.052.1
16. Limestone, thick bedded 3.755.8
17. Thin bedded shaly limestone; layers rather irregular; forming a prominent ledge extending fully 100 ft. east of the tunnel 3.559.3
18. Dark and light brownish impure limestone; often irregularly bedded; in layers 1.5 ft. thick. Lowest seen at upper end of tunnel 5.064.3

Smith's Quarry

It is no uncommon sight near the station at Union Springs to see huge piles of limestone on either side of the street, awaiting shipment to various points along the Lehigh Valley railway. Such rocks may be quarried at several places in this vicinity, but Smith's quarry, 1 mile east of the village, has of late furnished a large share of this material. If time permits and there are those still in need of exercise, a brisk walk to the quarry will prove both pleasant and profitable. The illustration given as Plate 8, shows the western face of this excellent rock exposure. It seems most surprising to see the steep southerly inclination or dip of the rocks, when the surface of the soil is so level. There is little doubt that the smooth farming land of this region owes its existence to the glaciers which scoured off the projecting rocks and filled up the lower places with the debris.

We are not to look upon these steep dips as due to fundamental disturbances of the earth's crust. They have not been produced by mountain making forces. Here, as at Frontenac Island, the dip changes very rapidly and is reversed in less than 100 yds. This local tilting may be due to some extent to the increase in bulk of the underlying beds, by the formation of gypsum from its anhydrite; but it is mainly caused by the dissolving of calcareous matter from various underlying beds, thus allowing the beds above to cave in or break down in a very irregular manner.

Notice here, as at quarry No. 7 (see map), the intercalation of black shaly seams among the heavy limestone layers. Near the top of the quarry black shale predominates. It looks smooth and dense on new fracture surfaces, but after a few months or years of weathering it splits into a multitude of lamellae and finally dissolves into tenacious clay, or if wet, sticky mud.

This is our first view at close range of the Marcellus shale. We see only the base of this substage here, for it has a total thickness of more than 100 ft. The peculiar rough weathering limestones strewn about over the quarry dump appearing to contain a considerable amount of ferruginous matter, came from the lower portion of the Marcellus shale, or in this quarry, from the topmost ledge exposed. We shall see the same exposed to better advantage at Quarry No. 7. Goniatite limestone is the name applied to this peculiar rock layer, for it often contains fragments of this Cephalopod genus. And, by the way, at this horizon this genus makes its debut into fossil society

We must not forget to look in the Onondaga limestone of this quarry for Trilobites of the peculiar form called Dalmanites selenurus . The anterior limb of the cephalon is peculiarly dentate and hence some authors prefer to call it by a new generic name, Odontocephalus (tooth-headed). The crescent shape of pygidium is what has suggested the specific name, selenurus (moon-tailed).

Before leaving this place it will be well to take a glance at the rise of ground to the east. See how long- drawn-out it -0 lit it is north and south. It has a drumlin-like appearance similar to the elevation extending front Cross Roads southward to Yawger's woods.

Quarry No. 7

About 1 mile south of Union Springs the upper part of the Onondaga limestone crosses the lake road and causes the grade to increase near the many rock quarries new and old. lit the first quarry to the left (going south) one observes a thick coating of glacial till with Marcellus shale beneath and still lower a good depth of Onondaga limestone. all in an approximately horizontal position. About a hundred yards or so farther on, the till has practically disappeared, while the same rock ledges are at a considerably higher elevation and show an anticlinal structure.

Here is a much better place to look for fossils in the Onondaga and Marcellus than at Smith's quarry. In the Onondaga fragments of Dalmanites sleenurus are by no means uncommon. But, the upper part of this stage is not particularly fossiliferous in this part of the State. A few fish teeth and plates may now and then be found; likewise small brachiopods of various genera. Notice the lack of the large corals so conspicuous in the lower beds of this stage, in Yawger's woods and adjoining fields. Notice too, the darker color of the rock, the intercalated shaly layers and the black chert bands and nodules. This upper portion of the Onondaga was formerly called the "Corniferous" limestone from the large number of cherty nodules it contained. it can be readily understood that when the limestone is dissolved away from these irregular shaped nodules, the latter stand out in bold relief like black knobs or horns; hence the name, Corniferous, from cornu , horn, and fero, I bear. Plate 9 shows a section in the quarry under discussion. From the water's edge to the ledge jutting out over the student's head, the Onondaga limestone makes up the section; from there upward, Marcellus shale prevails, its upper layer being calcareous and forming a distinct ledge as in Smith's quarry already described. In it fragments of Goniatites are often found. In the Marcellus shale large numbers of small Pteropods (Styliolina fissurella) and a Brachiopod (Leiorhynchus limitare) are coated with iron pyrites and show almost all colors of the rainbow; rainbow; especially are the golden and purple hues in evidence. A little towards the lake, across the road, a large amount of work has been done of late in a quarry alongside a switch leading north-easterly from the L.V.R.R. Here a local, very steep southerly dip can be seen and, if time permits, measured. Upper Onondaga layers compose the rock face of this exposure.

Shaliboo Quarry

Around a little to the southwest, perhaps a hundred dred yards, (see No. 8 on the map) the old Shaliboo quarry may be seen. It is grown over to a considerable extent with underbrush, but gives, nevertheless a fair rock section. See the following

Section at the Shaliboo Quarry

Ft. Thick
1. Onondaga limestone 12
2 Oriskany sandstone1/4
3 Dark, impure limestone layers1/4
4 Even bedded waterlime 4
5. Thick beds with Stromatpopra, Sp. vanuxemi, V. varistriata, Holopea, Leperitia, Meristella, and Orthothetes interstriatus 10
6. Heavy beds, dark colored, Megambonia and Tentaculites 4

Note that here you are looking again at the base of the Onondaga limestone, that large corals are common, but chert nodules and the trilobite, Dalmanites selenurus, rarely occur. The Oriskany sandstone horizon is very ferruginous and contains very few organic remains. Below, the Manlius beds are of a light drab, are even-bedded, and have very smooth jointplanes. Fossils are most abundant in the very basal layer of the quarry.

Farleys

Near Farleys a shallow body of water, known locally as Carr's Bay, indents the lake margin. South of the same, a low, wet stretch of land extends southward across the Farleys-Round Point road. West of and parallel to the depressed area is a ridge terminating to the northward in Long Point. This ridge may be looked upon as a low drumlin with rock core or base, similar to, though smaller than the long ridges already discussed. The upper beds of the Onondaga limestone may be seen at water's edge around Round Point, and out some distance in the water at Long Point. They dip below the level of the lake very quickly and for some distance only transposed rocks are seen along the shore. Naturally one would look for the Marcellus shale immediately upon the Onondaga, but just here it is worn away, and its place taken by glacial till. But in the Gully about 1/2 mile farther south, especially near the highway bridge most excellent exposures of this shale with its rich fauna can be found.

General Considerations and Resune

Land Surface

The land surface of the area included in the map (Pl. 1) is rolling, somewhat hilly in places though rarely broken. It extends from lake level (380 ft. above tide) to 770.

The present relief is brought about mainly by glacial abrasion and transportation and the dissolvent properties of subterranean waters. To the former may be ascribed the drumlimoid ridges, as well as' the prarie-like flat stretches of country underlain as we have seen at Smith's quarry by rocks tilted up at various angles. Likewise the small circular or oval depressions, generally called kettle holes may be due to the thawing out of a large nucleus of ice amongst glacial rock debris. As a rule, however, we believe that in this region, most of such depressions are caused by the caving in of surface material owing to dissolving away of the supporting calcareous rocks. That there has been and is still a great amount of work being done by underground water is proven by the fact that creeks, especially Yawger's, flow mainly in underground channels, and that lime sinks are numerous.

Stratigraphy

We have already seen that in the vicinity of Union Springs the older formations occur to the north, the younger to the south. In other words, the limestone with Eurypterus is older, dips under the gypsum; the latter passes beneath the upper Salina limestone; and this in turn beneath the Cobleskill. The Cobleskill dips under the Rondout; the Rondout disappears beneath the Manlius, the uppermost member of the Siluric system in this part of the State.

The basal bed of the Devonic here is the Oriskany sandstone which underlies the Onondaga limestone. Above the Onondaga comes the Marcellus shale, the highest, youngest rocks exposed in this vicinity. The following table perhaps shows the order of these rocks more clearly:

Rocks exposed in the vicinity of Union Springs

Feet

in Thickness

| Marcellus...................10+

Devonic.........| Onondaga....................125

| Oriskany....................0-4

| Manlius.................25

| Manlius..| Rondout.................40

| | Cobleskill...............8

Siluric..|

| | Drab colored I's........10

| Salina.. | Gypsum beds.............35

| Eurypterus..............25

The dip of the rocks in this region is extremely variable, as we have already observed in several localities. But in general it is southerly. From an inspection of the map one might suppose it to be south-east, for the trend of the stages seems to be north-east and south-west; but when it is remembered that the land slopes lakewards, it will be seen that the dividing lines between the stages do not represent true strike and the dip may be practically south.

Fossils

During the deposition of the Eurypterus-bearing limestone conditions seemed not very favorable hereabouts for animal life in general. Eurypterus and Leperditia seem to have been able to exist in very impure and salty water. During the tipper Siluric times conditions often favored these forms of life and hence they are widely distributed in rocks of this part of the geological column. The water lime rocks near Buffalo have furnished a large number of genera and species of the Eurypterus type, as may be seen by consulting the collections of the Museum of Natural History at Buffalo, N.Y.

Nothing seemed to have lived in the seas where gypsum was being deposited in large quantities. An abundant coral and brachiopod fauna returned with Cobleskill times and then retreated, and returned in a modified form in the Manlius.

The fauna of the Oriskany sandstone is very different from. that of any preceding stage. In fact, it ought to be, for from the end of Manlius deposition, to the beginning of Oriskany deposition was a very long time; time enough for the deposition of 150 feet of limestone rocks in the Helderbergs, time enough for the introduction and modification of several Helderbergian faunas. In the eastern part of the state too, the Onondaga does not lie immediately upon the Oriskany, but a hundred or more feet of Esopus shale intervene. So above and below the Oriskany there is in this region a missing link, or better a whole chain. It is therefore not strange that the fauna of the Onondaga is very different from that of the Oriskany.

The Devonic is often called the age of fishes, and so it seems to have been in some places, but in this part of the world fishes were not over abundant. Still, a few teeth or fin spines are now and then to be seen in the upper-most layers of the Onondaga limestone.

The black color of the Marcellus shales is doubtless due to, carbonaceous matter from decaying vegetation.

QUESTIONS

1. How high is the surface of Cayuga lake above sea level?

2. How high is the highest point on the map above the lake ?

3. Give a general idea of the depth of the lake near Union Springs

4. Where do the oldest rocks represented on the Union Springs map crop out?

5. Describe, give geographic distribution and thickness of the oldest substage represented in this area. Name and illustrate two of its charcateristic fossils.

6. State conditions of gypsum deposition. For what is the rock quarried ?

7. Describe the surface modifications brought about by the Gypsum bed.

8. State reasons for the absence of organic remains in gypsum rocks.

9. Describe the rocks immediately overlying the gypsum, and state whether or not they are fossiliferous.

10. Give thickness and lithologic characters of the Cobleskill beds. Describe some of the commoner fossils from Frontenac Island.

11. Give the substages of the Salina as here represented; the same for the Manlius.

13. Name and illustrate three common Manlius fossils.

14. The Cobleskill species are found to some extent in the Rondout, the Rondout species are found in the Manlius; why are not Manlius species found in the Oriskany sandstone?

15. Why is the Oriskany so variable in thickness?

16. Name and illiustrate three characteristic Oriskany species.

17. State lithologic and faunal difference between base and top of the Onondaga limestone.

18. In sections where the Oriskany is absent how can ou tell where the Manlius limestone ends and the Onondaga begins?

19. Distinguish between Marcellus and Onondaga faunas.

20. State general direction of dip in the region of Union Springs.

21. Give reasons for numerous steep local dips observed.

22. If the underlying rocks are tilted in various directions, why is not the surface of the soil more undulating ?

23. To what causes are the main topographic features of this region due?

24. Why are north-south ridges more prominent than east west?

END

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REPORT OF THE STATE PALEONTOLOGIST 1902

PRELIMINARY OBSERVATIONS ON THE COBLESKILL ("CORALLINE") LIMESTONE OF NEW YORK

BY C. A. Hartnagel

page 1129

Cobleskill Section at Union Springs, Cayuga Lake

The studies of Vanuxem extended as far west as Cayuga lake, the western limit of the third district. The last place where a line is sharply drawn between the Salina and the Waterlime recognized as consisting of three groups, is at Waterville, in Oneida county. From that place to Cayuga lake only one locality is mentioned where the brownish limestone, so characteristic of the base of his Waterlime group in the eastern end of the district, follows the Salina. This locality is near Jamesville, in Onondaga county. A number of quarries are mentioned about Cayuga lake, and a final disappearance of the group under the lake. The stratigraphic position of these quarries, however, is not clearly indicated.

In this connection it is interesting to note that Hall in speaking of the fourth or upper deposit of the Salina group, says:'

In Seneca county it does not appear in its usual characters; the highest rock of the group being a fine grained, dark colored, and grayish brown mass, which apparently represents the lower part

1Geol. N. Y. 4th Dist. 1843. p.129.

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page 1130 NEW YORK STATE MUSEUM

of this division. Between this and the succeeding limestone, there is an interval which is probably occupied by this mass, but too deeply covered to be visible. It appears, on the east side of Cayuga lake, coming down to the shore.

As will be shown later, the grayish brown mass represents the Cobleskill, the covered interval the Rondout and the succeeding limestone the Manlius.

Attention was first prominently called to the section under consideration by the late Prof. S. G. Williaims, in a Note on the Lower Helderberg Rocks of Cayuga Lake1 and in a paper on "The Western Extension of Rocks of Lower Helderberg Age in New York", published in the American Journal of Science.2 The section studied by Williams was in the vicinity of Union Springs and was included between the gypsum beds of the Salina and the Oriskany sandstone. From this section, having according to Williams a thickness of about 65 feet, he gives a list of 26 fossils, a number which were, according to the identifications, representatives of the Coeymans limestone and the New Scotland beds. It is evident, however, that Williams did not examine the upper horizons of this section that lie directly beneath the Oriskany sandstone, or he could hardly have failed to find a nearly typical Manlius limestone fauna and thus perhaps have reached a different conclusion as to the nature of the fauna about Union Springs. Though Williams in his determinations of the fossil forms seems to have been supported by such authorities as Hall and Whitfield, there can be no longer any doubt that the fauna was not properly construed in assuming any definite biologic or strati- relation to the Helderbergian series.

The distinctively Siluric aspect of this fauna was first estab- by Dr Clarke,3 who has also given considerable attention to the stratigraphy about Union Springs, which has resulted in accurately determining the position in the rock series of the outcrops on Frontenac island, from which the fauna of this section is mainly obtained. The accompanying map showing the geologic relations about Union Springs has been prepared by Dr

1 6th An. Rep't N. Y. State Geologist. 1897. p.10-12.

2 Ser. 3. 1886. 31:139-45.

3 N.Y. State Mus. Mem. 3.1900. p.99-101.

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REPORT OF THE STATE PALEONTOLOGIST 1902

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Clarke and Mr D. D. Luther, and it is with their permission that it is inserted in this paper.

The collections from the waterlimes of western New York by Mr Luther and notes bearing on the region examined, have been made available for my study and have given valuable suggestions in working out the relations of the Cobleskill. The study of the fauna front Frontenac island (Union Springs) and its comparison with the fauna of the Cobleskill of Schoharie county have had a very important bearing in showing that the "Coralline" or Cobleskill of Schoharie county is of post-Salina age. That a probable relationship existed between these two rock masses had already been suggested by Dr Clarke. In speaking of the species associated with the Eurypterus in the Salina beds of Cayuga and Herkimer counties, he Says:1

The study of these has indicated the probability that we may not be altogether secure in the time- honored interpretation and correlation of some of our other strata having similar lithologic characters , such for example as the Coralline limestone of Schoharie county and the waterlimes of the eastward sections. The fauna of a specially interesting outcrop of dark dolomite appearing on Frontenac island in Cayuga lake, where it is intercalated between the Waterlime strata, will, when fully studied, give important aid in the interpretation of the proper relations of these beds to those which they immediately precede in time and to which they are otherwise allied, that is to the true Helderbergian straata.

The probability of a relation existing between the beds of Frontenac island and the Cobleskill of Schoharie county, as thus expressed, may now be considered a certainty. As already indicated, the result given by Dr Clarke, relative to the unmistakable Siluric aspect of the section at Union Springs, is confirmed by a reexamination of the fauna, of which the stratigraphic relations as shown by the accompanying map, can leave no doubt as to the position of these rocks with reference to the true Helderbergian strata.

1N. Y. State Paleontologist. An. Rep't. 1902. p. 422.

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Frontenac Island

The best location for the collection of Cobleskill fossils in the vicinity of Union Springs is on Frontenac island in Cayuga lake, about 1/2 mile from the village. This island, having an area of one half acre, is the remaining part of the south limb of an anticline, which has its axis extending in a direction a little north of east and passing through Hibiscus point, 3/4 of a mile north of the island. The upward flexure of the strata at Hibiscus point brings the gypsum beds above the lake level, but the dip on the north side of the anticline makes them again disappear below the lake at a point opposite the railroad junction.

The surface of the island is nearly level and extends about 6 feet above the lake.

The outcrops of the Cobleskill on the island consist of three strata of hard, dark magnesian limestone, having a dip to the south of about five hundred feet to the mile, thus bringing into view the three layers, which together have a thickness of 8 feet, 6 inches. The upper layer, which is soft and quite dark, has a thickness of 3 feet, 2 inches and breaks readily into small angular fragments. With the exception of corals it is the most fossoliferous laver. The middle layer which is 2 feet, 10 inches thick, contains Stromatopora in abundance and, except that the color is a little darker, it is precisely the same in appearance as the Stromatopora bed of the Manlius limestone, holding a position 60 feet higher. The two upper layers are quite uniform in color, which is well retained even after they have been exposed for a considerable length of time. The lower layer, with a thickness of 2 feet, 6 inches, weathers a lighter color than the upper layers, is less fossiliferous and approaches more closely the character of the underlying Eurypterus beds.

The Cobleskill limestone where exposed on the mainland is also fossiliferous, but no species were found that do not occur on the island. The following list therefore represents Species identified from Frontenac island.

1 Chaetetes (Monotrypella) arbusculus Hall

2 Favosites niagarensis? Hall

3 Halysites catenulatus Linn.

4 Stromatopora concentrica Hall

5 Cyathophyllum hydraulicum Simpson

6 Crinoid sp.

7 Chonetes jerseyensis Weller

8 C. undulata Hall

9 Rhynchonella pisum Hall & Whitfield

10 Spirifer crispus var. corallinensis Grabau

11 S. vanuxemi Hall

12 Stropheodonta bipartita Hall

13 S. textilis Hall

14 S. varlstriata Con.

15 Whitfieldella sulcata Van.

16 Ilionia sinuata Hall

17 Megambonia aviculoidea Hall

18 Pterinea subpIana? Hall

19 Bucania sp.

20 Cyclonema sp.

21 Loxonema sp.

22 Trochoceras gebhardi Hall

23 Pleuroton-taria ? subdepressa Hall

24 Tentaculites gyracanthus Eaton

25 Gomphoceras septoris Hall

26 Orthoceras trusitum Clarke & Ruedemann

27 Orthoceras large sp.

28 Beyrichia sp.

29 Leperdifia alta ? Hall

30 L.cf. scalaris, Jones

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Distribution of the fauna from Frontenac island

A- Cobleskill at Cayuga Lake

B- Cobleskill, Schorarie Co.

C- Guelph

D- Manlius

E- Cobleskill at Buffalo

A B C D E

Chaetetes (Monotrypella) arbusculus XX
Favosites niagarensis?X?
Halysites catenulatus XX
Stromatopora concentrica XXX
Cyathophyllum hydraulicum XX
Chonetes jerseyensis XX
C. unduiata X
Rhynchonella pisum XX
Spirifer crispus var. corallinensis XX?
S. vanuxemi XX
Stropheodonta bipartita XX
S. textilis XX
S. varistriata XX
Whitfieldella sulcata XXX
Ilionia sinuata XXX
Megambonia aviculoidea XX
Pterinca subplana? XXX
Trochoceras gebhardi XXXX
Pleurotomaria ? subdepressa XX
Tentaculites gyracanthus XX
Gomphoceras septoris XX
Orthoceras trusitum XXX
Leperditia alta? XX
L. cf. scalaris XXX

The Cobleskill limestone appearing on Frontenac island also outcrops at the south end of Howland's point, 1/4 mile northeast of the island. The dip here is greater than on the island and the outcrop less favorable for collecting. The surface layers however contain large white Favosites, making a strong contrast with the dark color of the limestone. The surface as here exposed is in places polished and grooved by glacial action, thus indicating its resistant nature. A short distance from this outcrop on the northwest end of Howland's point there is an outcrop of the Salina waterlime carrying Eurypterus and an undescribed species of Lingula. This outcrop of the Salina shows that the beds of Cobleskill on Frontenac island immediately overlie the Eurypterus beds of the Salina.

The Cobleskill limestone is also exposed in O'Connor's old quarry 1 1/2 miles northeast of the island. The section in this

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REPORT OF THE STATE PALE ONTOLOGIST 1902

quarry shows 6 feet of Salina waterlime, with 4 feet, 8 inches of Cobleskill. The Stromatopora layer forms the upper surface of the Cobleskill.

The location of this quarry is about 85 feet above the lake, which shows that the average dip of the Cobleskill is about 120 feet a mile. It should be noticed however that in this region the dip varies greatly. This is due largely to the fact that the flexures of the strata have been produced by two sources and at different times. One set of flexures evidently is produced by horizontal pressure resulting in a general tilting of the rocks, the other by vertical pressure from below producing local disturbances, sometimes locally counteracting the effect of the general tilting of the strata and sometimes producing low conical elevations showing that the pressure was applied at a single point.

The pressure producing these local disturbances appears to be due to the increase in bulk of the underlying beds, in the formation of gypsum from its anhydrite. These beds of gypsum appear to be forming at the present time and they offer other interesting features, which can not be considered here. Excellent examples of these local disturbances can be seen in the field just north of O'Connor's quarry, where the Cobleskill is elevated into two cones, each having an elevation of 6 feet at the apex, where the rock is much broken and fissures are seen radiating from the center.

A short distance northeast of O'Connor's old quarry and at 15 to 20 feet higher there is another quarry in which 8 feet of Rondout waterlime is exposed. It will be seen from the position of these two quarries that the Cobleskill here holds the same position that it does in Schoharie county, namely, above the Salina and below the Rondout. The waterlime exposed in this quarry appears to be a good cement rock. It is dark in color, shows faint lines of deposition, and a tendency to split along these lines. A single segment of Eurypterus was found in the waterlime exposed-in this quarry.

The Cobleskill limestone again appears in the old quarry on the land of Mr John Wooley, about 3/4 of a mile south of Cross Roads. The part of the limestone which is exposed, is hard, dark

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1136 NEW YORK STATE MUSEUM

in color and has a thickness of 4 feet. The Stromatopora bed forms the upper surface. Below the Cobleskill there is exposed 12 to 15 feet of Salina waterlime, which becomes laminated and shaly on exposure. In the Salina a short distance below the Cobleskill, Lingula sp. undet. occurs.

A cut on the Lehigh Valley Railroad, 1/4 of a mile east of Cross Roads station, passes through beds of gypsum at what is known as the Thompson quarry. Above the gypsum in the banks east of the pit, there are about 25 feet of Salina waterlime, overlain by the Cobleskill, which is here much folded and broken. The upper part of the Cobleskill is covered, but the overlying dark Rondout waterlime shows slightly in the top of the cut on the south side and in the field above. Near the middle of the Salina waterlime in this cut fossils are quite abundant. Several species of brachiopods and fragments of Eurypterus occur. The Lingula sp. undet. already mentioned as associated with the Eurypterus at Howland's point, is found here extending to near the base of the waterlime. With the exception of a species of Leperditia, this Lingula appears to be the lowest fossil above the gypsum beds.

The elevation of the Cobleskill in this cut is 510 feet A.T., which is 120 feet higher than Frontenac island. This outcrop in the cut however is on the other limb of the snticline, with a dip strongly toward the northwest, showing that the actual dip of the rocks is much greater than the above figures would seem to indicate.

Manlius Limestone at Union Springs

The best exposure of the Manlius limestone in the vicinity of Union Springs is in the J. S. Shaliboo quarry, I mile south of the village. The part of the Manlius that is exposed is directly below the Oriskany sandstone. The upper layer of the Manlius is 4 feet 5 inches thick and quite free from -Stromatopora, but Leperditia alta Hall and a small species of Tentaculites are very abundant. The next layer below is a fine, dark blue limestone containing much Stromatopora. This is the layer which in appearance is similar to the middle layer of the Cobleskill on Frontenac island. to which reference already has been

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REPORT OF THE STATE PALEONTOLOGIST 1902 page 1137

made. The third laver contains less Stromatopora, while in the fourth layer it is absent. The lower layers weather nearly a uniform color. -The following species have been identified from this quarry.

1 Chaetetes (Monotrypella) arbusculus Hall

2 Stromatopora sp.

3 Orthothetes interstriatus Hall

4 Spirifer vanuxemi Hall

5 Stropheodonta varistriata Con.

6 Whitfieldella laevis var. ?

7 W. sulcata Van.

8 Holopea antiqua Van.

9 Tentaculites sp.