GEOLOGY OF THE ATTICA AND DEPEW QUADRANGLES 1 9 



of the stream, cascades have been produced with the limestone 

 at the crests and long exposures in the banks farther down the 

 stream. The larger and more accessible of these exposures are : 

 on Bowen creek 2 miles northwest of Alexander ;, on Murder creek 

 30 rods below the bridge at Darien ; on EUicott creek one and three- 

 fourths miles west of Darien Center; at west end of Erie Railroad 

 cut 2 miles east of Alden ; in the bed of Durkee creek at 900 A.T. 

 and in the bed of a small stream flowing into Cayuga creek 2 miles 

 south of West Alden. , At the Bullis bridge over Buffalo creek the 

 Tichenor limestone is the crest of the fall, and is bare to the extent 

 of half an acre above. It is displayed in the cliffs below the fall for 

 one-quarter of a mile and the bed of the stream is strewn with large 

 blocks from it. The Ludlowville and ^loscow shales are also finely 

 exposed, making this an exceedingly interesting as well as pic- 

 turesque locality. 



The limestone is well exposed in the bed of Cazenovia creek be- 

 low the bridge at Spring Brook and also at the crest of a cascade 

 in a small branch of Cazenovia creek, near the west line of the 

 quadrangle 2 miles north of Webster Corners. 



MOSCOW SHALE 



This formation rests on the Tichenor limestone and consists in 

 these quadrangles of about 50 feet of soft, light bluish gray sliales 

 that are usually somewhat calcareous and embrace several courses 

 of flat concretions. The latter become at some exposures continu- 

 ous concretionary layers crowded with fossils. Eastward from On- 

 tario to Chenango counties the light colored Moscow is separated 

 from the black Genesee shale by the Tully limestone, but west of 

 Canandaigua lake and on these quadrangles this limestone and 

 the Moscow beds are directly followed by thin lentils of iron pyrite 

 or black shale. 



Like most of the Devonic formations, the Moscow diminishes in 

 thickness toward the west. At Moscow in the Genesee. River valley, 

 the locality from which the term Moscow shale is derived, the beds 

 are 130 feet thick and on the south side of the mouth of Eighteen 

 Mile creek at North Evans they measure but 17 feet. 



Moscow shale is everywhere exceedingly rich in fossils, but the 

 specimens are, as a rule, not so well preserved as in the Ludlow- 

 ville sliale, and there is little difference between the faunas of the 

 Moscow and Ludlowville shale. Doctor Grabau reported 51 species 

 from the Moscow beds in the Eighteen Mile creek region, the fol- 

 lowing being the more common forms : 



