MAGNETITE IRON DEPOSITS OF SOUTHEASTERN NEW YORK II 
was very prevalent at that time, and one which has been subscribed 
to by most geologists who have followed Kitchell. 
The geological survey of New Jersey was discontinued at the 
beginning of 1857; from that time until its revival in 1864 geological 
work was at a standstill in that state. Nor is there any record of 
activity in Highland geology in the State of New York during that 
interval, with the exception of a short paper by Credner * which 
is devoted chiefly to a description of the geology of Manhattan 
island and vicinity. Credner, however, imagined that the rocks from 
Manhattan island to Peekskill and beyond were a transitional series, 
and thought he could trace the gradual changes from the “ gneiss ” 
(that is, the Manhattan schist) on Manhattan island, to hornblende 
gneiss, hornblende schist, to syenite, and “ hypersthenite.”’ No such 
gradations exist, nor was Credner’s work ever taken very seriously 
by American geologists. 
The legislature of the state of New Jersey made the necessary 
appropriations for the continuance of the survey in 1864, and in 1868 
the final report of Dr George H. Cook,’ the state geologist, was 
published. A considerable portion of this report is devoted to a 
description of the magnetite mines of the state. Doctor Cook drew 
largely on the previous work of Kitchell and quoted him at length. 
He agreed with Kitchell that: “ . . . everything in structure, 
position, and attendant minerals, shows that the ore is in sedimen- 
tary beds, the same as the gneiss is.” (p. 533) 
There is, however, in this report, a much better and more sys- 
tematic discussion of the geology of the “Azoic formation” (Pre- 
cambrian crystallines) of the Highlands area than had heretofore 
appeared, and mention is made of folds which affected the ore beds 
in some of the mines. 
Most of the succeeding work on the Highlands geology from 
this time centered on the magnetite deposits. The sedimentary 
origin of the ore beds was considered fully established by all 
geologists, so that their efforts were directed principally toward the 
recognition of some constant relation between the ore bodies and 
their containing rocks, and to detailed descriptions of the iron mines. 
The only new observation of moment is recorded in the Annual 
Report of the State Geologist of New Jersey for 1872'* wherein 
Smock, the assistant state geologist, referring to prospecting opera- 
11 Credner, Herman. Sa Skizze der Umgegend Von New York: 
Zeitschr. Deuts. Geol. Gesell., 388-08. 1865. 
12 Cook, George H. The Gales of New Jersey; Newark, 1868. 
13 Annual Report of the State Geologist of New Jersey, 1872. 
