67 



River, a distance of about eight miles, is low and sand}'. 

 The countr\^ for some distance back from the lake, is low, 

 level farm or swamp land. The shale appears in the bed of 

 Smoke's Creek, near West Seneca, containing- Liorhvnchus 

 limitaris (Conr. ). The exposure is about a mile and a half 

 from the shore, and its consideration does not properly 

 belong here. 



General Summary of the Lake Shore Sections.— Taking a 

 general view of the lake shore clifts, we notice that the\' 

 furnish a continuous section from the Marcellus to the upper 

 Naples shales. Of the former, less than twentv feet are 

 exposed, these representing the upper olive shales of the 

 formation. The greatest thickness of the Marcellus in 

 Western Ncav York, according to Professor Hall, is not over 

 fift}^ feet.* The thickness of the rock in Erie County is 

 probably somewhat less. 



Resting on the Marcellus shales, are the thirtv feet of 

 Transition rock, terminated by the Strophalosia bed. These 

 are by some included in the Hamilton stage, but their rela- 

 tion is probably more with the Marcellus, and they are here 

 placed with the latter. The whole thickness of the Lower 

 or Hamilton shales — about fifty feet — is exposed, beginning 

 with the Nautilus bed. 



The note-worth}'- beds included in the Hamilton shales are 

 as follows: First, at the base, the three Pleurodictyum 

 beds, (the lowest of which is the Nautilus bed ). Second, the 

 three Trilobite beds, beginning between nine and ten feet 

 from the base. Third, the lithologically similar bed, six feet 

 above these, or eighteen feet from the base, ( noteworthy 

 mainly on account of its persistence). Fourth, the Modio- 

 morpha subalata bed, twenty-five feet from the base. Fifth. 

 the Athyris spiriferoides layer forty-one feet from the base. 

 Sixth and seventh, the Demissa and Stictopora beds, 

 between four inches and a foot from the top. 



•Rep't -ith Geol. Dist. 1843, p. 179. 



