CANANDAIGUA AND NAPLES QUADRANGLES 



21 



term altogether. At Tichenor point the limestone is exposed 

 along the roadside at the opening of the ravine and it reappears 

 on the shore of the lake jnst south of Tichenor point where it 

 forms a low but well marked anticline cut off at one end by a 

 slight displacement. Here it dips under the water and reappears 

 at the north side of Menteth point forming a broad platform at 

 the water level. 



These are the best outcrops of the formation known in Ontario 

 county and the rock also appears slightly in the lower part of 

 the Miles gully in Hopewell and on Flint creek south of Castle- 

 ton. A limestone of similar character is exposed in the bed of 

 Beebe brook, West Bloomfield, but it is not altogether certain 

 that it belongs to this horizon. 



Moscow shale 



The Tichenor limestone is overlain by a mass of mostly soft, 

 light bluish gray calcareous shales, becoming darker toward the 

 upper part. Thin layers of limestone usually extending but a few 

 rods and irregular calcareous lenses largely composed of fossils 

 are of frequent occurrence. At the base of the mass lying im- 

 mediately on the Tichenor limestone the shale is very compact 

 and highly calcareous and breaks out in irregular slabs. This 

 portion of the deposit is very persistent over a wide area and is 

 characterized by the abundance of crinoids which it contains in 

 the most admirable preservation. Indeed this is the horizon 

 which has furnished all the superior crinoid material from these 

 rocks in this part of the State. It is this layer, which with the 

 Tichenor limestone has in previous reports, specially the descrip- 

 tion of the geology of Ontario county published by the writer, been 

 designated as the Encrinal band. An exposure of this layer on 

 the farm of Mr Sisson, not far from the village of Muttonville, 

 now Vincent, in the northern part of the town of Bristol, afforded 

 to the collectors of the State Museum in 1860, C. A. White and 

 C. Van Del oo, an immense amount of fine material, constituting 

 the best preserved and most complete series of crinoid calyxes 

 ever obtained from the rocks of this State. This exposure is 



