244 SEE— FURTHER RESEARCHES ON [April 24, 



40,000 feet. Of course, it is impossible that such thickness could accumulate 

 on the same spot without pari passu subsidence of the sea-floor. In fact, 

 we have abundant evidences of comparatively shallow water at every step 

 of the process — evidence sometimes in the character of the fossils, some- 

 times in the form of shore-marks of all kinds, sometimes in the form of 

 seams of coal, showing even swamp-land conditions. Again, of course, the 

 sediments were thickest and coarsest near the shore-line, and thinned out 

 and became finer towards the open sea, i. e., westward. Finally, after 40,000 

 feet of sediments had accumulated along this line the earth-crust in this 

 region gave way to lateral pressure, and the sediments were mashed together 

 and folded and swollen up into the Appalachian range. Subsequent erosion 

 has sculptured it into the forms of scenic beauty which we find there to-day. 



" 2. Sierra.- — This was apparently the first-born of the Cordilleran family. 

 Its history is as follows : During the whole Palaeozoic and earlier part of 

 the Mesozoic, there was in the Basin region a land-mass, whose form and 

 dimensions we yet imperfectly know, but whose Pacific shore-line was east 

 of the Sierra. The Sierra region was therefore at that time the marginal 

 bottom of the Pacific Ocean. Probably the position of this shore line changed 

 considerably at the end of the Palzeozoic. The extent of this change we 

 will discuss hereafter. Suffice it to say now that, during the whole of this 

 time, the Sierra region received sediments from this land-mass until an 

 enormous thickness (how much we do not know, because the foldings are 

 too complex to allow of estimate) was accumulated. At last at the end 

 of the Jurassic, the sea floor gave way to the increasing lateral pressure 

 along the line of thickest sediments, and these latter were crushed together 

 with complex foldings and swollen up into the Sierra. An almost incon- 

 ceivable subsequent erosion has sculptured it into the forms of beauty and 

 grandeur which characterize its magnificent scenery. 



" 3. Coast Range. — The birth of the Sierra transferred the Pacific shore- 

 line westward, and the waves now washed against the western foot of that 

 range, or possibly even father westward in the region of the Sacramento and 

 San Joaquin plains. At this time, therefore, the region of the Coast Range 

 was the marginal bottom of the Pacific Ocean. During the whole Cretaceous, 

 Eocene, and Miocene, this region received abundant sediments from the now 

 greatly enlarged continental mass to the eastward ; until finally, at the end 

 of the Miocene, when 30,000 feet of sediments had accumulated along this 

 line, the sea-floor yielded to the lateral pressure, and the Coast Range was 

 born ; and the coast-line transferred to near its present position. 



" 4. Wahsatch. — The physical geography of the region to the east of 

 the Wahsatch (Plateau region) during Jura-Trias time is little known. But 

 during the Cretaceous the region of the Wahsatch was the western marginal 

 bottom of the great interior Cretaceous Sea (see map. Fig. 760, p. 486), 

 receiving abundant sediments from the great land-mass of the Basin and 

 Sierra region. This greatly increased the enormous thickness of sediments 

 already accumulated along this line in earlier times. At the end of the 

 Cretaceous the sediments yielded, and the Wahsatch was born. It is neces- 

 sary, however, to say that both the Sierra and Wahsatch underwent very 



