Y/EAVER: INVERTEBRATE PALEONTOLOGY AND HISTORICAL GEOLOGY 719 



gradually being arrived at. The important monographs on the Cambrian faunas 

 from the Canadian Rockies in Alberta by Walcott have made possible the divi- 

 sion of that system into three series which serve as a standard for comparison 

 with other areas. 



Surveys made by the geological surveys of Russia and India have shown the 

 presence of extensive areas of early Paleozoic sedimentary marine rocks in north- 

 ern Asia southward into China and also the transgression of the Indian Ocean 

 over parts of western India. Recent investigations show that rocks of early 

 Paleozoic age occur across parts of New Zealand and Australia, in northern 

 Africa, and in the central and western parts of South America. 



Upper Paleozoic: The Devonian of Great Britain is represented by the Old 

 Red Standstone, which had been made known through the writings of Hugh Mil- 

 ler prior to 1850. When it was realized that these rocks occupied a stratigraphic 

 position between the marine fossiliferous beds of the Cambrian-Silurian and the 

 Carboniferous of Devonshire and Cornwall, they were designated in 1837 as the 

 Devonian system by Sedgwick and Murehison. Since 1850 they have been the 

 subject of many detailed studies by British geologists and now are recognized as 

 of flood-plain and eolian origin. The most complete Devonian sections from 

 both a stratigraphic and faunal standpoint occur in the Rhineland and Eifel 

 areas of western Germany. During the past one hundred years many important 

 contributions have been made to the Devonian rocks and faunas in Russia, cen- 

 tral Asia, and South America. In southwestern Australia Devonian rocks con- 

 sisting of shales and sandstones are reported to have a thickness of nearly 25,000 

 feet. 



By 1850 the areal distribution and broad lines of classification of Carboni- 

 ferous rocks were fairly well known. During the past one hundred years many 

 monographs have appeared with descriptions of the faunas and floras and many 

 modifications of stratigraphic classification. In most parts of Europe these rocks 

 have been and still are termed Lower and Upper Carboniferous in contrast to 

 the Mississippian and Pennsylvanian systems of North America. The Carboni- 

 ferous of Germany has been subdivided by Lottner (1868), by H. B. Geinitz 

 (1856), and by F. von Roemer (1870). The Lower Carboniferous beds of West- 

 ern Europe consist largely of fossiliferous limestone, in contrast to carboniferous 

 sandstone and shale in the Upper. Eastward into Asia limestones have been 

 found to prevail. 



The association of coal, oil, and gas in rocks of Upper Paleozoic age in eastern 

 and central North America has resulted in detailed investigations of these for- 

 mations by State and Federal surveys. The areal and structural geologic maps 

 of large areas of the United States have made known the lithology, thickness, and 

 structure of the Devonian, Carboniferous, and Permian rocks and the classifica- 

 tion of their subdivisions. The Carboniferous system has been recognized by the 

 U. S. Geological Survey, with the Mississippian and Pennsylvanian as sub- 

 systems. These investigations point out the contrast between the strongly folded 

 and faulted beds of the Appalachian area and the slightly tilted strata of the 

 central part of the continent and also with the faultblock structures of the 

 Cordilleran region. 



A twofold series of uppermost Paleozoic rocks occurs in northern Germany 

 between the Carboniferous and the overlying Triassic beds. The lower part of 



