PALEOGEOGRAPHY OF THE MESOZOIC 507 



also common to the entire Pacific Coast region, for nowhere are there, 

 according to Smith, any marine Khsetic strata. To emphasize this marked 

 diastrophism, the period of orogenic mountain-making has recently heen 

 named the Chitistone Disturbance, after the thick limestone of the same 

 name, so well developed in southeastern Alaska. 



In this connection it is well to direct attention to the fact that the 

 Triassic of eastern North America was also deformed at the close of this 

 period. The Palisade Mountains of Dana, a series of faulted or block 

 mountains, were in existence then from Nova Scotia to South Carolina, 

 a distance of 1,000 miles. This disturbance is known as the Palisade 

 Disturbance. 



JVRASSW TIME 

 (See Figure 4) 



It was stated that the Triassic period closed with crustal warping and 

 deformation all along the entire Pacific border of North America, and 

 that mountain-making on a considerable scale took place at least through- 

 out Alaska. In consequence the sea appears to have been removed every- 

 where from the continent. 



The Pacific Ocean again began to invade North America early in Juras- 

 sic time, sparingly in the Aleutian peninsula, the Cook Inlet country of 

 Alaska, and across Vancouver Island. Of Middle Jurassic events little is 

 as yet well known, other than that the Lower Jurassic of Alaska, with a 

 thickness of 1,000 to 4,000 feet, continues, according to Stanton and 

 Martin, unbroken unto the Middle (1,500 to 2,000 feet) and Upper 

 Jurassic (5,000 -feet). The total thickness of the marine Jurassic in 

 Alaska exceeds 10,000 feet, and consists essentially of coarse deposits, 

 such as tuffs, conglomerates, sandstones, and shales, with andesitic lava 

 flows near the top of the series. This is largely the material from the 

 Chitistone Mountains, formed at the close of the Triassic. 



In the Californian Sea, an independent faunal province of Oregon, 

 California, and Nevada, sedimentation appears to have been continuous 

 throughout Jurassic time, but the detail of the formations is well known 

 only locally. The strata of the Gold Belt series — the Mariposa and 

 Auriferous formations — of northern California and Oregon are essentially 

 sandstones and shales, with very little of limestone and about 500 feet of 

 tuffaceous conglomerates. In places the thickness is 2,000 feet, rising to 

 over 6,000 feet elsewhere in California, and if the Lower Knoxville strata 

 of 10,000 feet thickness, with their Jurassic flora, belong here, the maxi- 

 mum thickness will rise considerably above the last-mentioned figure. In 

 the Humboldt Range of Nevada there are from 1,500 to 2,000 feet of 



