2 GEOLOGY. 



of these areas were the sites of salt seas, and some of fresh lakes, while 

 still others may have been free from standing water. Within the gen- 

 eral area of deposition, many areas of relatively high land probably 

 interrupted the continuity of the sedimentation. 



At about the time when the open sea was generally excluded from 

 the western interior, the ocean began to creep in on the western border 

 of the continent, and the shore of the Pacific was presently shifted 

 eastward to the 117th meridian in the latitude of Nevada. 



As a result of these changes in geography, the Triassic strata are 

 known in three regions: (1) The Atlantic slope east of the Appala- 

 chians; (2) the western interior; and (3) the Pacific coast. The 

 strata in these three regions are so widely separated, and in many 

 ways so unlike, that they will be considered separately. 



The Triassic System (Newark Series) of the East. 



Distribution. — From Nova Scotia on the north to South Carolina 

 on the south there is a series of belts or patches of rock of Triassic 

 age, representing the oldest post-Paleozoic system on the eastern side 

 of the continent. The beds of these several areas have been grouped 

 under the name Newark 1 (from Newark, N. J.). 



The areas where the strata of the system are now exposed are 

 shown on the accompanying map (Fig. 307). Of their existence east 

 of their exposures nothing is known. 



It will be observed that the belts and patches where Newark strata 

 come to the surface are mostly elongate in a northeast-southwest 

 direction, and that their longer axes are roughly parallel to the Appa- 

 lachian Mountains and to the present coast line. Of the series, there 

 may be said to be four principal areas. These are: (1) the area about 

 the Bay of Fundy; (2) the area in the Connecticut River valley; 

 (3) the long belt extending from the Hudson River in the southern 

 part of New York, through New Jersey, Pennsylvania, and Mary- 

 land into Virginia; (4) a number of relatively small disconnected 

 areas in Virginia and North Carolina. From what has preceded, and 

 from the general principles already understood, it is needless to say 

 that the Newark series is unconformable on the older formations on 

 which it rests. 



1 For an account of the Newark series see Russell, Bull. 85, U. S. Geol. Surv., 1892 

 Full bibliography to date of publication. 



