634 PRINCIPLES OF STRATIGRAPHY 



prints. Fish remains and shells of Estheria are found in inter- 

 calated black shales, and terrestrial plant remains are not uncom- 

 mon in some sections. Much feldspar occurs and this together 

 with the oxidation of the iron compounds indicates the relative 

 aridity of the climate. Intrusive sheets and lava flows characterize 

 the northern development, and coal beds the southern. Barrell 

 and Kiimmel have brought forward evidence in the sediments that 

 a part of the material in Connecticut and in New Jersey was de- 

 rived from the east as well as from the west. They therefore 

 consider the deposits as formed in large basins bounded by faults, 

 rather than accumulations on a coastal plain surface. Until re- 

 cently the Triassic deposits of eastern North America were inter- 

 preted as estuarine accumulations (Russell-48; Chamberlin and 

 Salisbury-ii), but the detailed study of the physical characters 

 of the rocks has developed the evidence which shows them to be con- 

 tinental deposits (Barrell-5). Similarly the corresponding Triassic 

 deposits of northern and western Europe, the New Red sandstone 

 of England and the Bunter Sandstein and Keuper of Germany had 

 been regarded as estuarine, tidal, or lake deposits (Reade-46), 

 but their subaerial origin, as sediments deposited by rivers chiefly 

 from the mountains of that period on the south and west, is being 

 more generally recognized. On the Continent the material was 

 chiefly derived from the old Vindelician mountain range which 

 existed where now is the valley of the Danube and separated the 

 Alpine Triassic sea from the North German lowlands. According 

 to Brauhauser (Fraas-22 :5/5) the pebbles of the Lower Bunter 

 sandstein of Schramberg are not worn by rolling, but the pebbles 

 of the conglomerate forming the base of the Middle Bunter are 

 well rounded and their size decreases from southeast to northwest. 

 The material is derived from the crystallines and from the Rothlie- 

 gende of the Permic. Wind-cut facetted pebbles also occur, but 

 they have been more or less worn by subsequent reworking. Wal- 

 ther (58:79) speaks of middle and eastern Europe in Lower 

 Triassic time as a huge desert area supplied with variable detritus 

 by streams from the mountains on the south and west, and covered 

 by endless dunes, interspersed with ponds, and once at least by 

 a large relict sea. Clastic material accumulated to a depth of 400 to 

 600 meters, after which the sea invaded the region from the east 

 and the marine Muschelkalk was deposited. An earlier temporary 

 and partial invasion of the sea is suggested by fossiliferous hori- 

 zons. The Keuper marks a return to continental sedimentation, 

 which in Switzerland, France, and England was uninterrupted. 

 At the beginning widespread sandstones (Schilf sandstein) were 



