CANANDAIGUA AND NAPLES QUADRANGLES 



23 



The upper part of the Moscow shales is exposed on the east side 

 of the lake in the Gage creek ravine where, about 50 feet above 

 the Menteth limestone, a series of nodular layers of limestone 2 

 feet thick form a low cascade. Also in the ravines of Bennett's 

 landing, Gooding landing. Long point and along the lake road and 

 shore to the Gorham-Middlesex town line. The same series is 

 displayed on the west side of the lake from i mile south of Black 

 point northward to Foster point, and in the upper parts of the 

 Menteth, Tichenor and Hope point gullies. They are shown in the 

 bed of Shaffer creek J mile north of the Gooding schoolhouse 

 near the western boundary of Canandaigua township and also 

 in the Bristol valley in several small ravines on the east side be- 

 tween South Bloomfield and Vincent, and in the lower part of the 

 ravine on the east side of Baptist hill. 



Tully limestone 



Ontario county includes the westernmost and final appearance 

 of this important, though relatively thin, rock formation. In the 

 towns of Geneva and Seneca to the east and also in Gorham, 

 except close on the shore of the lake, this limestone appears with 

 constantly diminishing thickness, and its last appearance is in 

 Gage creek about 40 rods east of the eastern boundary of the map. 

 Here it is a bed of dark bluish gray, hard, brittle limestone and at 

 its last exposure attains a thickness of 2 feet and 8 inches. Doubt- 

 less the stratum extends a mile or more beyond this point to the 

 southwest, as some loose blocks 8 inches thick, apparently but 

 slightly displaced, lie in the bottom of the small gully at the side 

 of the road leading eastward up the hill from Bennett's landing. 

 Eastward of this region and throughout central New York as far 

 as Chenango county the Tully limestone is prominently developed 

 and attains at its maximum a thickness of from 20 to 30 feet. On 

 the Canandaigua sheet at all other exposures except those men- 

 tioned, the Moscow shales beneath and the Gorham shales above 

 are in contact or separated by lenticular discontinuous layers of 

 iron pyrites from 10 to 50 feet on the edge and 1 to 4 inches in 

 thickness, the material of which is very hard and in damp places is 



