Charles Schucliert — Historical Geology, 1818-1918. 65 



bildungen von Texas, but it was not until 1887 that 

 Robert T. Hill showed in the Journal (33, 291) that it 

 included two great series, the Gulf series, or what we now 

 call Upper Cretaceous, and a new one, the Comanche 

 series. This was a very important step in the right 

 direction. Since then the Comanche series has been 

 regarded by some stratigraphers as of period value, 

 while others call it Lower Cretaceous ; the rest of the 

 Texas Cretaceous is divided by Hill into Middle and 

 Upper Cretaceous. On the other hand, Lower Creta- 

 ceous strata had been proved even earlier in the state of 

 California, for here in 1869 W. M. Gabb (1839-1878) and 

 J. D. "Whitney (1819-1896) had defined their Shasta 

 group, which was wholly distinct faunally from the 

 Comanche of Texas and the southern part of the Great 

 Plains country. 



Jurassic and Triassic of the West.-. — In 1864, the Geo- 

 logical Survey of California proved the presence of 

 marine Upper Triassic in that State, and since then it 

 has been shown that not only is all of the Triassic present 

 in Idaho (where it has been known since 1877), Oregon, 

 Xevada, and California, but that the Upper Triassic is 

 of very wide distribution throughout western North 

 America. Jurassic strata, on the other hand, were not 

 shown to be present in California until 1885, while in the 

 Rocky Mountain area of the United States there was 

 long known an unresolved series of "Red Beds" sit- 

 uated between the Carboniferous and Cretaceous. This 

 gave rise to the "Red Bed problem," the history of 

 which is given by C. A. White in the Journal (17, 214, 

 1879). In 1869, F. V. Hayden announced the discovery 

 of marine Jurassic fossils in this series, and since then 

 they have come to be known as the Sundance fauna, 

 extending from southern Utah and Colorado into Alaska. 

 Above lie the dinosaur-bearing fresh-water deposits, 

 since 1894 known as the Morrison beds. In 1896, 0. C. 

 Marsh (1831-1899) announced the presence of Jurassic 

 fresh-water 'strata along the Atlantic coast (2, 433), but 

 to-day only a small part of them are regarded as of the 

 age of the Morrison, while the far greater part are 

 referred to the Comanche or Lower Cretaceous. The 

 red beds below the Jurassic of the Rocky Mountain area 

 have during the past twenty years been shown to be in 

 part of L^pper Triassic age and of fresh-water origin, 



Am. Jour. Sci.— Fourth Series, Vol. XLVT, No. 271.— July, 1918. 

 3 



