14:^ AXXALS yEW YORK ACADEMY OF SCIEXCES 



the faculty of the Department of Geology at Princeton University, Dr. 

 Edgar T. Wherry of Lehigh University and Dr. L. Hiissakof of the 

 American Museum of Xatnral History, Xew York City. 



History 



The Lockatong formation is the middle member of the sedimentary 

 series of the Triassic system, as exposed in the adjacent parts of Xew 

 Jersey and Pennsylvania. Elsewhere throughout the Triassic of eastern 

 Xorth America it is unknown. 



The earliest reports dealing with the rocks of this formation mention 

 them only in connection with the quarrying industry of the region. 

 Thus, in the Annual Eeport of the State Geologist of Xew Jersey for^ 

 1880 (p. 24), a short statement is made concerning Stephen Margerum's 

 quarr}^ in Princeton, which was first opened in 1845. In the issue of this 

 publication for the following year (p. 55), a similar allusion appears. 

 F. L. Nason's discoveries of- fossils from the Triassic, reported in 1888 

 (idem, p. 28), include those found in the Lockatong beds. B. S. Ly- 

 man^ wrote a report on the New Eed of Bucks and Montgomery Cotm- 

 ties, in which the rocks of this middle member are described and named 

 Gw^^nedd shales. Because however this term was made, on the map at 

 least, to cover rocks clearly referable to other formations, it seemed best 

 to the Xew Jersey geologists to rename the formation, and in the de- 

 tailed report Dr. H. B. KummeP proposed the term Lockatong, which is 

 now generally used. This was further supplemented by an even more 

 detailed paper, published by him in his report for the following year.* 

 In 1908, Professor J. Volney Lewis made a careful investigation of the 

 argillites of this series, the results of which were published in the State 

 Geologist's Eeport for that year (p. 94). Since that time, descriptions 

 of the Lockatong have appeared in the Philadelphia Folio (Xo. 162), 

 and in the Trenton Folio (Xo. 167), of the Li"nited States Geological 

 Survey, in both of wliicli excellent geological maps of the respective areas 

 are given. 



DlSTRIBUTIOX AND TOPOGRAPHY 



The rocks of this series lie in a slightly curved belt extending from a 

 point some ten miles west of Phoenixville, Pa., to the border of the Cre- 

 taceous formation about ten miles northeast of Princeton, N. J. (See 



2 Summary Final Report of the Second Pennsylvania Geological Survey, vol. 3, part 2, 

 p. 2G10. 1895. 



3 Kept. State Geologist of N. J., 189G, p. 40. 

 * lhi(J.. 1897. p. 8G. 



