REVIEW OF AUTHORITIES. 115 



Emmons stated : " The Utica slate, in the gorges of Lorraine and Rod- 

 man [in the southern part of Jefferson county], is about 75 feet thick; it 

 is, at least, less than 100 feet" (Geol. N. Y., pt. ii, p. 118) ; and also he 

 said : " I am satisfied that its thickness never exceeds 75 feet " (ibid., p. 

 400). Vanuxem considered its thickness and reported it as " often show- 

 ing a thickness whose maximum is about 250 feet" (Geol. N. Y., pt. iii, 

 p. ^>G). Dana said : " The Utica shale is 15 to 35 feet thick at Glenn's 

 Falls, in New York, 250 feet in Montgomery county, 300 feet in Lewis 

 county " (Manual Geol., p. 196). Finally, Mr Walcott stated : "At the 

 typical locality in the vicinity of Utica the formation has a thickness of 

 over 600 feet" (Trans. Albany Inst., vol. x. 187'.), p. 1). This statement 

 was repeated in 1888 when the Campbell well was described, in the record 

 of which 710 feet was referred to the Utica shale (Proc. Am. Assoc. Adv. 

 Sci., vol. xxxvi, p. 212). Walcott stated in 1890 that " at Utica the Utica 

 shale is 710 feet in thickness " (Bull. Geol. Soc. Am., vol. i, p. 347). 



P. — Mr Walcott reported that in the Campbell well, west of Utica, there 

 was probably 330 feet of Trenton limestone, and in the vicinity surface 

 outcrops 290 feet in thickness (Proc. Am. Assoc. Adv. Sci., vol. xxxvi. 

 p. 212). Vanuxem stated that the Trenton limestone at Copenhagen, 

 Lewis county, "must be 300 feet thick, showing a great increase in its 

 progress from the Mohawk river, where in no place is it 30 feet in thick- 

 ness " (Fourth Ann. Rept. Third Geol. List. N. Y., pp. 364, 365); also, 

 '• on the Mohawk its thickness rarely exceeds 30 feet, but it increases 

 through Oneida and Lewis, being 300 feet in the north part of the 

 latter county" (ibid., p. 371). In his final report this statement is 

 repeated as follows : " The greatest thickness of the Trenton limestone is 

 in Lewis county, toward the northern end, where it cannot be less than 

 300 feet. It diminishes in thickness going east and south, rarely exceed- 

 ing 30 feet in any part of the Mohawk valley. It is not so thick at the 

 east as at the west end " (Geol. N. Y., pt. iii, p. 49 ; also, see similar 

 statement on p. 268). Emmons said : " The greatest thickness which I 

 have been able to give to the Trenton limestone is 400 feet. At Chazy, 

 where it is made up of alternating beds of limestone and shale, this, 

 according to the best estimate I can make, is the thickness of this rock. 

 The gray variety is, however, wholly wanting at this locality ; if that is 

 to be considered as a distinct mass, the whole thickness may be greater 

 than I have given it ; but at Watertown, where both varieties exist, the 

 thickness cannot much exceed the above estimate. At Glen's Falls it is 

 much less "(Geol. N. Y., pt. ii, p. 116); also, "the thickness of the 

 Trenton limestone at Watertown, including the whole mass, which 

 extends south, and which is embraced in the section, is about 300 

 feet" (ibid., p. 388). The Black River limestone " is about 10 feet thick 



XVII— Bull. Gkol. Soc. Am., Vol 4, WX2. 



