AMERICAN 445 



of which it is composed. The rocks of this Newark series were 

 evidently formed from the waste of the granite and crystalline 

 schists in the neighbouring hills, for the sandstones are largely 

 felspathic and micaceous. The sedimentary rocks of the Appa- 

 lachian range did not contribute to the formation of the Triassic 

 deposits, their drainage being to the west, for the metamorphic 

 ridges to the eastward effectually cut off the Appalachian streams 

 from the Triassic estuaries. 



It is still a question whether these inland bodies of water were 

 originally separated or continuous, though it seems probable that 

 all the areas lying to the southwest of the Hudson were thus con- 

 nected, while those of the Connecticut valley and Nova Scotia 

 may have been formed in another continuous body of water. Evi- 

 dences of tidal action are to be seen in the rocks of both of these 

 estuaries. Fossils are rare in these rocks, and none of marine 

 origin have been found ; land plants and the footprints of land 

 animals are the commonest fossils, but in some localities fishes 

 are quite numerous. 



The sedimentary rocks of this estuarine Trias are much faulted, 

 and some of the dislocation appears to have taken place while the 

 sediments were still in process of deposition. The beds are also 

 cut by many dikes of diabase, and sheets of the same are inter- 

 calated between, the strata. Some of these sheets are contempo- 

 raneous lava flows, and indicate much volcanic activity during 

 Triassic times ; others are intrusive, and, with the dikes, belong to 

 a later series of disturbances. These igneous rocks everywhere 

 accompany the Triassic strata, from Nova Scotia to North Caro- 

 lina. 



The rarity of fossils makes the exact reference of the Newark 

 series a matter of uncertainty, but the evidence favours the con- 

 clusion that these rocks belong in the upper part of the Triassic 

 system. 



In the interior region a large part of the continent was covered 

 by a great, but shallow inland sea, which must have been shut off 

 from the ocean. What are now the mountain ranges of Colorado 

 formed one long island, reaching from Wyoming to New Mexico. 



