402 R. S. Lull — Life of the Connecticut Trias. 



In general geologists now regard the theory of the conti- 

 nental deposition of the Connecticut valley sediments as definitely 

 proven. 



The Physical JEnviromnent. 



The weight of evidence seems to show that the physical en- 

 vironment within which the animals of the Triassic lived con- 

 sisted of several broad depressions along what is now the north- 

 ern Atlantic coast. It is, nevertheless, inconceivable that 

 creatures of such ample locomotive powers as the majority of 

 the Connecticut valley remains would imply were limited to 

 the actual troughs, but they must have roamed far and wide 

 across the uplands as well, though naturally their records of 

 wanderings would only be made where sedimentation was in 

 progress. 



The climatic conditions of Triassic times may be judged by 

 three criteria : the character of the sediment itself, the physical 

 phenomena impressed upon the strata, and the evidence of the 

 organic life. 



Barrell (1908, p. 183), who has made extensive studies. upon 

 the relations between climate and sedimentation, comes to the 

 conclusion that the "dominant red color of the whole of the Tri- 

 assic formation, considered in connection with its feldspathic 

 sandstones, indicative of the kind of erosion, mud-cracked shales, 

 disseminated gypsum, and calcite, indicative of conditions of 

 sedimentation, point ... to a subarid climate," and further- 

 more that "the Triassic conglomerates . . . are associated with 

 many features of climatic significance . . . which independently 

 indicate a semiarid climate with hot summers and possibly cold 

 winters " (p. 259). 



Tenner (1908, p. 305), in describing the shales of the New 

 Jersey Newark areas, summarized the physical phenomena 

 thus : 



"They are finely comminuted siliceous material, strongly im- 

 pregnated with oxide of iron. Their laminations may be 

 paper-like in thinness, but are generally coarser. On exposure 

 to the weather they break up into a multitude of crumbly 

 fragments. Mica scales are very plentiful. The surfaces of 

 the laminae frequently show a multitude of irregular markings 

 — grooves, pits, curved lines, lumps, smooth patches of 

 irregular shape, etc., not all of which can be deciphered with 

 any certainty. Many, however, can be identified. Mud- 

 cracks, rain-pits, and worm-grooves are frequent. Kill-marks 

 are sometimes found. At times films of impalpable sediment 

 are found in the depressions in the lumpy surfaces of certain 

 sandstone layers, which, in their delicate markings, suggest 

 irresistibly the frothy scum left in hollows after a rain." 



