112 C. S. PROSSER — DEVONIAN AND SILURIAN ROCKS. 



he stated that the thickness of the Onondaga limestone " rarely exceeds 

 10 or 14 feet " (ibid., p. 132), and at Vannep's, near Perryville, Madison 

 county, ho gave the thickness as " about 10 feet" (ibid.., p. 135). Dana 

 wrote : " In New York the thickness of the limestone seldom exceeds 20 

 feet for the Onondaga and 50 feet for the Corniferous " (Manual Geol., 

 p. 250'. Emmons reported 100 feet of Onondaga and Corniferous lime- 

 stone at Cherry Valley, in Otsego county (Agri. X. Y., table on p. 178; 

 also see statement on p. 175). From the above statements it appears to 

 be a fair estimate to call the ( !orniferous limestone of our section 60 feet 

 thick and the Onondaga limestone 10 feet. 



G. — Yanuxem said : "'At Oriskany Falls [southwestern corner of Oneida 

 county], to the north of the village the sandstone is exposed for some 

 distance, forming a ledge or mass about 20 feet thick " (Geol. X. Y.. pt. iii. 

 p. 125) ; while " the greatest thickness in the district is on the old Seneca 

 road between Elbridge and Skaneateles [in the western part of Onondaga 

 county], appearing to be about 30 feet thick" (ibid., p. 283, and see 

 p. 126). Emmons reported: "At Oriskany Falls, 20 feet; at Perryville 

 and below Cazenovia, only a few inches " (Agri. X. Y., p. 170). 



H. — Professor S. G. Williams stated: " The exposure of lower Helder- 

 herg rocks at Oriskany Falls, 18 miles south of Utica, is interesting, partly 

 because it is so laid open by deep and extensive quarries as to give nearly 

 a complete section of about 120 feet of rocks, 115 feet of which can be 

 definitely measured from the Oriskany sandstone, here 10 feet thick, 

 down to the bank of the abandoned Chenango canal " (Am. Jour. Sci., 

 3d ser., vol. xxxi, p. 142). Emmons reported 121 2 feet at Cherry Valley, 

 Otsego county (Agri. X. Y., table on p. 178). 



I. — Yanuxem. in 1840, reported " a thickness in Onondaga county of 

 about 7<H) feet" (4th Ann. Rep. Third Geol. Dist. X. Y., p. 375); while 

 in his final report he stated that the "thickness gradually increases 

 toward the west [from the Hudson river], and reaches its maximum in 

 the counties of Onondaga and Cayuga, where it is not less than 700 feet " 

 (Geol. X. Y., pt. iii, p. 96) ; also, the red shale of this group is said to 

 have <>reat thickness in Onondaga county, " being more than 500 feet 

 thick at Salina, which the deep boring of 1839 made known" (Yanuxem. 

 5th Ann. Pep. Third Geol. Dist. X. Y.. 1841. p. 147). This was also re- 

 stated in the final report (see Geol. X. Y.. pt. iii. pp. 278, 279). Professor 

 Hall reported that on a line from Seneca or Ontario to Oswego county 

 it is "more than 1,000 feet in thickness" (27th Ann. Rep. X. Y. Stale 

 Mus. Nat. Hist,. 1875, p. 128, and Proc. Am. Assoc. Adv. Sci.. vol. xxii, 

 1874, B, p. 332); while Dana says: "They [the Onondaga Salt group 

 beds] are 700 to 1,000 feet thick in Onondaga and Cayuga counties and 

 only a few feet on the Hudson " (Manual Geol., p. 233). Emmons re- 



