136 Prof. J. D. Dana on some Results of 



The other geosynclinal belt of the Cretaceous era was to the 

 west of the Sierra Nevada, as described by Whitney. This coast 

 geosynclinal ended in extensive displacements and plications, 

 much metamorphism, and a high synclinorium. 



6. The intermediate region, the Great Basin, which had been 

 widened at the close of the Jurassic by the annexation of the 

 plicated and consolidated Sierra and Wahsatch, was the era of a 

 geanticlinal, or at least of absence of subsidence ; for King says 

 no Cretaceous rocks occur over it. 



7. With the close of the Cretaceous, or when the Cretaceous 

 synclinorian movements of the sea-coast and mountains were 

 ending, a geanticlinal movement of the whole Eocky-Moun- 

 tain region began, which put it above the sea-level, where it 

 has since remained. This upward movement continued through 

 the Tertiary. 



8. During the Tertiary age, until the close, probably of the 

 Miocene Tertiary, another pair of parallel geosynclinals, but 

 geosynclinals of Tertiary formation, were in progress. The 

 Cretaceous synclinoria had given still greater breadth and sta- 

 bility to the relatively stable region between them; and one of 

 these new troughs is hence further east on the mountain side, 

 and the other further west on the coast side. 



In the coast geosynclinal, marine tertiary beds were accumu- 

 lated to a thickness of 4000 to 5000 feet ; and then followed the 

 epoch of disturbance ending in another coast synclinorium, a 

 coast range of mountains, in some places metamorphic, and 

 having ridges, many of which are at present 2000 feet or more 

 in height above the sea, and some in the Santa-Cruz range, 

 according to Whitney, over 3500 feet. 



basin, and that over this basin betweenjthe Green River and the Wahsatch 

 no single instance of conformity occurs between the coal-beds and the over- 

 lying horizontal freshwater strata. As stated above, he makes the epoch 

 of Cretaceous uplifting to have followed, not the Cretaceous period, but 

 the earliest period of the Tertiary, Eocene beds being, in his view, included 

 with the Cretaceous in the folds referred to. 



Dr. Hayden has investigated with much detail the Green-River basin 

 and the region east of it, and years since announced that the Lower Ter- 

 tiary beds in some parts of the Rocky-Mountain region were tilted at a high 

 angle. He has held that all the coal-bearing strata were Lower Tertiary, 

 but now agrees with the view expressed by King, and first suggested by 

 Meek, that part are Cretaceous, while another part are Lower Tertiary, and 

 considers the later Tertiary beds (which lie unconformably on the beds 

 below in the regions of disturbance) Miocene and Pliocene. He states that 

 the thickness of the Cretaceous formation in the Laramie plains is 8000 to 

 10,000 feet. He observes in a recent letter to the writer that the coal- 

 bearing strata and Cretaceous are never [unconformable, but instead are 

 often folded together, and sometimes stand at a high angle, even vertical 

 in many places— as in the Laramie Plains south of Fort Sanders, along the 



