156 GEOLOGY OF THE TmRD DISTRICT. 



Orthis rcsupinata or the Upside-down orthis, Bufo calymene, and the genus Gryphaeus ; but 

 this fact does not hold to the east of the lake, where their range is more extensive. So also 

 with the Recurved cypricardite, which I only found in that part, on the lake, under the TuUy 

 Umestone at Ludlowville. This fossil holds a lower position east, being one of the numerous 

 ones near West-Hamilton, in the sandstone portion of the group. These facts are given to 

 •show the difficulty of establishing differences in the group to the east of Cayuga lake, and 

 not that differences do not exist to the west of it ; for as shale greatly predominates at that 

 end of the State, and mixtures at the east end, tin obvious constancy as to the position or 

 vertical range of fossils may exist at the one, and may not exist, or not be very apparent at 

 the other. 



The Moscow shales may be seen between the two limestones in any of the ravines, or small 

 brooks which flow into the lake from Long point to Hemrod's point, and from thence along 

 the lake shore to Bloom's lime-kiln. Similar shales, but generally harder, appear under the 

 Tully limestone at Montville, Moravia, Vanetten's mill in Sempronius, Tully four corners 

 and Tinker's falls; at all which localities the Tully limestone appears, and beyond also 

 where the limestone has run out, as at Smyrna, the creek at Sherburne, and at North New- 

 Berlin ; or at least we find at all these places a more fine-grained and softer shale, with 

 numerous and similar fossils, succeeding harder shales and sandstone ; but whether they are 

 the same with the Moscow shales, will depend upon a comparative examination of their fossils, 

 which has not yet been made, and which must be subject matter for the Report on the Fossils 

 of the State. 



From the great thickness of the group, and the extent of surface which it covers, it pre- 

 sents numerous points for examination ; deep and broad valleys being excavated in the group, 

 into which numerous brooks, flowing from the hill-tops, discharge their waters, often pre- 

 senting one or more cascades, where a harder portion of the group has arrested the destruc- 

 tive action of their waters. 



In Otsego county, among the numerous favorable points for examining some portions of 

 the group, is the brook by the ashery just below Cherry- Valley village. The part at the falls 

 consists of the coarse shale, and contains numerous fossils, such as the two varieties of the 

 Mucronated delthyris, the Concentric atrypa. Keeled atrypa, Undulated conularia, Gryphaeus, 

 etc. Higher up on the hill are harder and sandy varieties of the group, but too much covered 

 up to admit of much examination. 



The brook on the west side of the valley, two miles lower down, exhibits the finer and 

 more fissile shale, then the coarser, and finally the sandstone variety towards the top of the 

 hill, which appears as a ledge, showing numerous specimens of the Flabella avicula, the 

 common one of the group. 



Between Clarksville and Cherry- Valley on the east side, and on the side-hill, the coarse 

 shale appears with the fossils, among which is De Kay's dipleura, parts of which are fre- 

 quently met with from the first district to Cayuga county. 



