118 



Report of the State Geologist. 



the top of these calcareous shales is twenty-seven feet, which mass of rock the 

 writer regards as belonging to the same horizon as the Tully limestone of 

 western central New York. This outcrop was first described in 1887 and 

 was the farthest east that the Tully had been traced 1 until the exposure 

 near Smyrna village was discovered, which is described in the present paper. 

 From my observations on the eastern outcrops of the Tully limestone, I 

 ascribe its disappearance to a gradual loss of the calcareous material which is 

 replaced by that of the arenaceous and argillaceous sediments, causing the 

 rock to present a decidedly different lithologic appearance. This is sub- 

 stantially the explanation advanced by Professors S. G. Williams 2 and Henry 

 S. Williams. 1 



X VIII < r s . For a short distance above the calcareous shales the rocks 

 are covered, but where the stream forks black fissile shale begins and about 

 ten feet are shown. For. forty feet above the black shales the rocks are mostly 

 hidden, but at this point are thin sandstones one-quarter to one-half inch in 

 thickness, with an occasional layer of black shale between them. Fossils 

 were not found in these black, argillaceous shales, which are regarded as 

 belonging to the Genesee slate. As a portion of the rocks is concealed, it is 

 difficult to give their thickness, but from a study of the exposures a little 

 northwest of this locality, it seems probable that they have a thickness of 

 twenty feet or more, perhaps of forty feet, as stated by Professor S. G. 

 Williams. 4 



XVIII 6r 4 . Just above the thin sandstones of the run already described 

 are thicker sandstones, while the shales change to a blue or olive color; on 

 their upper surface are frequent irregular markings, perhaps partly due to 

 Fucoids, but mainly to mud markings produced by mechanical causes. 

 Above the highway the rocks are mainly blue, smooth shales, which weather 

 to an olive color and split into very thin pieces. In these fine shales no fossils 

 were found. Put not far from the run above described another crosses the 

 highway, the first one below Upperville, and in this, about thirty feet above 

 the highway, is the Wilcox quarry, which has been worked for building 

 stone, the heaviest layer being nineteen inches thick. There is an occasional 

 thin flag layer and the sandstones alternate with shales. Fossils are rare, 

 only a very few specimens being found in an hour's search, as the list 

 shows : 



iSee Piosser, Proceedings American Association Advancement Of Science, Vol. XXXVI, p. 210; and 8. G. Williams, Sixth 

 Annual Report State Geologist [New York], p. ik. 



• Sixth Annual Report State Geologist [New York], 1887, p. 18. 

 3 Bulletin Geological Society of America, Vol I, 1>90, p. 490. 

 4 Sixth Annual Report State Geologist (New York], p. 18. 



