30 GEOLOGY. 



the areas which had been the sites of deposition to a higher level, fault- 

 ing the rocks, and affecting them by igneous intrusions. These changes 

 were comparable in extent and importance to the changes which sepa- 

 rate various systems of the Paleozoic series, but they were not of con- 

 tinental dimensions. The rocks of the next system are not repre- 

 sented north of Maryland, and perhaps nowhere in the Atlantic and 

 Gulf plains. In the western part of the United States, there seem 

 to have been no physical changes of great moment separating the 

 Triassic from the Jurassic, and the sedimentary history of much of 

 that part of the continent seems to have run an uninterrupted course 

 from the beginning of the first of these periods to the later part of 

 the second. The case may have been somewhat different north of 

 the United States, for in British Columbia and in the adjacent islands, 

 Triassic and older formations were upturned, deeply eroded, and 

 again submerged before the beginning of the Cretaceous. The great 

 igneous formations associated with the Trias of the northwest appear 

 to have been made during the Triassic period, rather than at its 

 close. The greatest body of igneous rock referred to this period, the 

 great batholith of the Coast Range, is nearly 1000 miles long. 1 



Foreign Triassic. 

 Europe. 



The Triassic formations of Europe are found in widely separated 

 localities. The largest exposed area is in northeastern Russia, but 

 the system is much better known in some other parts of the continent, 

 especially in Germany and England. It is also known in most of 

 the southern countries, though its outcropping areas are relatively 

 small. In England, the system is unconformable on the Permian 

 and older beds, thus showing that sedimentation was interrupted 

 after the Permian period. On the continent, on the other hand, the 

 Triassic system is generally conformable on the Permian. 



The Triassic system of Europe has two somewhat distinct phases, 

 known as the Triassic (largely non-marine) and the Alpine (marine) 

 phases, repectively. The Triassic phase of the system is developed 

 with more or less modification throughout the northern part of the 



1 Dawson, Geol. Soc. of Am., Vol. XII, p. 89, and Brooks, Geol. Soc. of Am., Vol. 

 XIII, p. 260. 



