522 INDEX TO THE STRATIGRAPHY OF NORTH AMERICA. 



the Reward Mill, and about 1,500 feet up above the mill, on the Union Wash trail from Inde- 

 pendence over the Inyo Range into Saline Valley. The fossils were submitted by Dr. Walcott 

 to the writer for identification, and referred to the Lower Trias, on the basis of the occurrence of 

 several genera characteristic of the Brahmanic stage of the Scythic series in the Oriental region. 

 In a preliminary report the writer did not venture to describe new species or genera, but noted 

 the occurrence of Nannites, Clypites ?, Koninckites, Meekoceras, Kingites, Gyronites ?, Xenaspis, 

 Dinarites, and a new genus of Tropitidse. Later collections and better material have confirmed 

 most of these identifications, but the form referred to Clypites has proved to be a new genus of 

 the same group; the supposed Kingites is very uncertain; the Dinarites has turned out to be a 

 Paralecanites ; and the supposed new genus of the Tropitidse belongs to the Hungaritidse. 



Later collections, by Mr. H. W. Turner, of the United States Geological Survey, and by the 

 writer, have added greatly to the list of genera and species, bringing out even more strongly the 

 relations of this fauna to the Brahmanic faunas of the Asiatic regions. 



At the base of the section seen on the Union Wash are massive sihceous and calcareous 

 beds supposed, on the basis of fossils found in the float, to belong to the Carboniferous; then 

 several hundred feet of calcareous shales with obscure traces of ammonites; then about 15 feet 

 of hard gray sihceous limestone, from which all the fossils hsted from this horizon were taken. 

 Above this hmestone lie about 800 feet of dark shales with a few impressions of ammonites; 

 then about 5 feet of impure earthy black limestone with numerous ammonites, Ptychites, Hun- 

 garites, Acrochordiceras, Xenodiscus, thought by the writer to belong to the base of the Middle 

 Trias, or the Subrobustus beds of the Oriental region. 



Lindgren ^^^ describes the Sailor Canyon formation and associated slates, 

 quartzites, and schist in the Colfax quadrangle, California, west of Lake Tahoe, 

 as "Juratrias," having found ammonites and other shells in the beds. 



J-K 18. NEW JERSEY, PENNSYLVANIA, AND MARYLAND. 



The Newark group is typically developed in New Jersey, and the rocks occur 

 in several distinct belts from Massachusetts to North Carolina. ^^^ 



The Triassic sediments of New Jersey and New York were described without 

 definite subdivision prior to the work by Kiimmel,^" from which the following 

 extracts relating to the separate formations (Stockton, Lockatong, and Brunswick) 

 and the associated igneous rocks are taken. 



The Newark series consists of sedimentary and igneous rocks. The former are cliiefly 

 shales, sandstones, and conglomerates; the latter diabase, to which the more general term trap 

 has usually been applied. Along the Delaware River the sedimentary rocks are divisible, on 

 lithological grounds, into three groups, which have been called Stockton, Lockatong, and 

 Brunswick. i 



Stockton group. — The basal beds of the series are found at Trenton, where they rest uncon- 

 formably upon the older crystalhne rocks. They consist of (a) coarse, more or less disintegrated 

 arkose conglomerates; (b) yellow, micaceous, feldspathic sandstone; («) brown-red sandstones 

 or freestones; and (d) soft red argillaceous shales. These are interbedded and many times 

 repeated, a fact which indicates rapidly changing and recurrent conditions of sedimentation. 

 Although there are many layers of red shale in tliis subdivision the characteristic beds are the 

 arkose conglomerates and sandstones, the latter of which afford valuable building stones. 



In addition to the cross-bedded structure which often prevails in the sandstones, mud 

 cracks and impressions of raindrops occur. The rapid alternation from conglomerates to shales 

 and vice versa, the changes in composition in individual beds, the cross-bedding, ripple marks, 

 etc., all indicate very clearly that these beds were deposited in shallow water in close proximity 

 to the shore. The bulk of the material of which they are composed was derived from the crystal- 

 line rocks on the south and southwest, but where they were found to rest upon Silurian shales. 



