SUMMARIES OF PRE-CAMBRIAN LITERATURE 
OF NORTH AMERICA 
EDWARD STEIDTMANN 
University of Wisconsin 
V. THE EASTERN PART OF THE UNITED STATES 
During the period covered by these summaries, the following 
United States Survey quadrangle areas containing pre-Cambrian 
rocks have been mapped: the Raritan quadrangle of New Jersey, 
the Tolchester quadrangle of Maryland, and the Ellijay quadrangle 
of Georgia. The New York State Museum has published several 
papers on Adirondack areas. The Federal Survey has published 
Emerson’s bulletin on the “‘Geology of Massachusetts and Rhode 
Island.”’ 
One of the most notable advances is the determination of the 
pre-Cambrian age of the Wissahickon mica gneiss of southeastern 
Pennsylvania by Bliss and Jonas. In Vermont, the unconformable 
contact between Cambrian and pre-Cambrian has been more 
clearly defined by Dale and by Keith. The Ocoee group in the south 
is now placed by the Federal Survey with the Cambrian. This is 
still largely a matter of arbitrary decision. The apparently con- 
formable gradation of Ocoee into Cambrian is interpreted by 
Keith and associates as evidence of the Cambrian age of the Ocoee. 
’ The lack of fossils in the Ocoee has been emphasized by Van Hise 
and Leith as a pre-Cambrian trait. 
The Raritan quadrangle’ lies in both the Appalachian and 
Coastal plain provinces of northern New Jersey. For purposes of 
mapping, the pre-Cambrian rocks of the quadrangle are classified 
as the Franklin limestone, Pochuck gneiss, and graphite schists, 
all of sedimentary origin. The Byram gneiss is a gray granitoid 
igneous rock composed of microcline, microperthite, quartz, and 
?W. S. Bayley, R. D. Salisbury, and H. B. Kummel, “Description of the Rariton 
Quadrangle, New Jersey,” U.S. Geol. Surv., Geol. Atlas, U.S. Raritan Folio (No. 191) 
(1914). 32 pp., 21 figs., 5 maps, section sheet. 
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