426 NEW YORK STATE MUSEUM 
part of Montgomery county and extends to the southeastward, 
coming out in great force at Glens Falls where it is extensively 
quarried for black marble. . . The lower massive series appears 
to be an older member of the formation overlapped westward and 
apparently to some extent near its southern termination by the 
thin bedded series.”! ‘This massive series is developed “in the 
region about Amsterdam and eastward to the Hoffman ferry 
fault. . . becoming somewhat thicker and coarser grained in 
the easternmost exposure. In the quarries and stream cuts north 
of Amsterdam there are exposed 17 feet of the coarse grained mas- 
sive series, here rather thinner bedded than usual. At the exten- 
sive quarries [Weatherwax] two miles northwest of Hoffman ferry 
the lower member is very coarse grained, soft, massive bedded, 
highly fossiliferous limestone and has a thickness of about 20 feet” 
{p. 426). 
Utica shale. This mass is included with the Transition Gray- 
wacke of Eaton as in part at least the slaty variety.2~ Mr Conrad 
included the Utica in part with the Trenton, for he says “ the rock 
is chiefly a fissile slate, but as it passes north it assumes as at Tren- 
ton Falls the character of a dark blue, very hard fetid limestone. 
The slate is frequently traversed by veins of calcareous spar.’ 
Vanuxem first spoke of the Utica as the black shale which appears 
from under the rubblestone (Hudson river) and extends from east 
to west throughout the county (Montgomery).! 
Mather calls the Utica the Mohawk slate group and says that 
it “ passes into the Trenton by gradual interstratification.’® 
In the Fourth annual report of the third district Vanuxem says 
“there is no mineralogical difference between the shale which 
separates the dark colored layers of the Trenton limestone and this 
rock, but though in many localities it contains thin beds or flags 
of limestdne in the lowest part of its mass, yet we often find above 
these thin beds a thickness of two or more hundred feet without 
any limestone whatever.’’é 
In Vanuxem’s final report this rock is designated “ Utica slate,” 
and is described as “of a deep bluish black, generally fissile, ex- 
18th annual report N. Y. state geologist, 1893, p. 424, 425. 
*Geological survey district adjoining Erie canal, p. 91. 
*First annual report third district (N. Y.) Assembly doc. no. 161, p. 163. 
“Second annual report third district, Assembly doc. no. 200, p. 258. See also p. 283. 
*Fifth annual report first district, Assembly doc. no. 150, p. 91, 92. 
*Loc, cit, Assembly doc. no. 60, p. 371. 
