22 NEW YORK STATE MUSEUM 
the geology of the Highlands in 1891; a report by Wolff ** on the 
Archean geology, in which he recorded attempts to unravel the 
structure and origin of the gneisses at Hibernia by using a horizon | 
marker sufficiently characteristic to enable him to trace it for con- 
siderable distances. Wolff used a phase of the gneiss composed of 
quartz, feldspar, biotite, garnet, magnetite and often graphite, which 
weathered to a deep red color. He favored “an origin for the 
series from a previous bedded series by metamorphism and 
re-crystallization which took place contemporaneously with the 
folding and without fusion” (p. 369), thus arguing a like origin 
for the associated magnetites; a paper by Nason *’ in which he 
described the folded structure of the ore bodies in the Ringwood 
mines, and, having apparently abandoned his earlier suggestion as 
to the possible igneous origin of the ores, very definitely stated that 
“no beds of iron-ore have been observed to cut across the plane of 
bedding as they would do in case of their secondary origin, either 
from their being of eruptive origin (an idea now obsolete), or from 
having been deposited in veins or fissures of fractures.” (p. 508) 
Belonging to this period also is a paper by Westgate *° who studied 
the gneisses of Jenny Jump mountain and found them to be massive 
granitoid rocks with an absence of crumpling and contortion, and 
with no well-defined schistosity. He found no evidence that these 
rocks had ever been folded and found it impossible to connect the 
different belts with one another except by “inventing ’’ synclines or 
anticlines in order to explain the recurrence of the belts, which he 
felt was useless, since the observed facts failed to support any such 
theory. 
Westgate found no evidence in proof of the detrital origin of the 
lighter colored feldspathic varieties of the gneiss, but on the con- 
trary stated that the massive character of the granitoid gneiss 
suggested an igneous origin. At the northern end of the mountain, 
however, hornblendic and micaceous gneiss and quartz pyroxene | 
rock occur associated with the limestone and apparently interbedded 
with it; he believed these to be metamorphosed sediments. 
Westgate made a very thorough study of the crystalline lime- 
stone associated with the gneisses. There was at that time a 
44 Wolff, J. E. The Geological Structure in the Vicinity of Hibernia, New 
Jersey, and Its Relation to the Ore Deposits. Annual Rep’t State Geol. Geol. 
Surv. N. J., p. 359-69.’ 1893. 
45 Nason, F. L. The Geological Structure of the Ringwood Iron Mines, 
New Jersey. Trans. A. I. M. E. 24: 505-21. 1804. 
46 Westgate, L. G. The Geology of the Northern Part of Jenny Jump 
Mountain, in Warren County, New Jersey. Annual Rep’t State Geol. Geol. 
Surv. N. J., p. 21-62. 1895. 
