THK LIMESTONES. 245 



difficulty of getting reliable evidence. The area in Gouverneur township 

 and neighborhood on which the above conclusions were based has been 

 since enlarged and studied in greater detail (as shown in Dr Smyth's 

 paper immediately following this), but without altering the earlier conclu- 

 sions. Smyth has also made some observations on the extension of the 

 Norian in the southwestern border of the Adirondack region * and, al- 

 though he does not mention the })resence of limestones, Vanuxem f states 

 that an " aggregate of granular carbonate of lime and coccolite . . . 

 and some singular aggregates of a similar kind, with feldspar, having tlie 

 a})pcarance of a In-eccia, but evidently the result of accretion," are found 

 in the primary area of Herkimer county. 



Emmons J says, " primary limestone appears at intervals throughout 

 Hamilton county accompanied with its usual associate, serpentine; " 

 and Mather § mentions the beds of white limestone in Washington 

 county between Fort Ann and WhitehalL 



The Limestoni<:s of the Region. 



g en era l dis trie ution. 



With this latter reference we are brought around to the eastern side 

 again, in the region covered l)y the field-work of this paper. As this 

 especially concerns Essex count}^ it may be added that the limestones, 

 both of the white and the serpentinous variety, occur in Warren county 

 in notable amounts. There are quarries some eight miles northeast of 

 Thurman station, on the Adirondack railway, which have had a brief 

 period of activity, and various small exposures of the white variety which 

 have been burnecl more or less for lime. At North creek there is a very 

 considerable thickness well known in connection with the natural bridge 

 near that })lace, and the same area possibly extends into Essex county 

 at Newcomb. 



3fODE OF OCCURREXCE AXD ASSOCIATED ROCKS. 



The limestones and their associated rocks always occur in depressions, so 

 far as my ob-servations have gone, for the resistant ridges are of the harder 

 gneiss or anorthosite. They form geologic sections as extensive as 1,000 

 feet, in which, however, tlie limestone strata are much less than half, 

 and in which the true thickness is very difhcult to determine because of 

 varying dips, schistosity, the frequent possibility of faults, and the like. 

 There seems to be no question that the limestones are really old calca- 



•On GahJiroH in the Soiithwostern A(Jiron<lin;k Region. Am. Jour. Sci , July, 1894, p. 54. 

 t Report on the Third DiHtrift, p. 2.").".. 

 ; Rf port on Second Di»t)ict, p. 416. 

 ^ Report oD First District, p. 486. 



