632 HISTORICAL GEOLOGY. 



Carboniferien, Calcaire Carbonifere et Terrain Houiller, E. de Beaumont, 



D'Orbigny. 

 Carboniferous Period, Dana, Man. GeoL, 1st. edit., 1863 and later. 

 Penusylvanian, H. S. Williams, U. S. Geol. Surv., Bull. 80, 1891. 



1. SuBCAKBONiFEROus Period. — Mountain, or Carboniferous, limestone, tbe 



lower division of the Carboniferous system, Murchison, Lyell, etc. 

 Lower Carboniferous. Lower part of the Systeme Carboniferien, Calcaire 



Carbonifere, D'Orbigny, Lapparent. P>ergkalk, Uutercarbon. 

 Subcarboniferous, D. D. Owen, RejJ. Geol. Wiscoyisin, Iowa, and Minnesota, 



1852 ; Dana, Man. Geol., 1863 and in subsequent editions. 

 Subcarbon, Steinmann and Doderlein, Elem. d. Pal., 1888. 

 Mississippian, H. S. Williams, U. S. Geol. Surv., Bull. 80, Correlation of 



the Devonian and Carhoniferoiis, 1891. 

 Eocarboniferous, H. S. Williams, Journ. Geol., Chicago, 1894. 



The comprising of the Permian period and the Carboniferous in a 

 common era is questioned by some geologists. In North America the 

 Permian beds are a direct continuation of the Carboniferous, and from the 

 general absence of vertebrate and invertebrate fossils they are scarcely 

 separable in most regions except through a careful study of the fossil plants. 

 Such a study, made for Pennsylvania and Virginia in part by Lesquereux, 

 but with completeness by Fontaine and I. C. White, has afforded satisfactory 

 proof, as they state, that the Permian is fully represented in eastern America, 

 and that the period is here only a continuation of, or a closing addition to, 

 the Carboniferous period. There is the same evidence from the plants and 

 also from the nearly universal conformity in the stratification of the two 

 formations as to the close relations of the two periods in Europe, and this 

 is sustained paleontologically, as these authors remark, " by the investiga- 

 tions of Weiss, Grand' Eury, and others." 



The other continents were not so well supplied with coal-making areas as 

 North America and Europe. South America has the rocks over part of its 

 great interior, with little of the coal, and is in this respect like the western 

 half of North America, 



Asia has much coal of the Carboniferous period in northern China. But 

 in India, or southern Asia, the chief coal era began in the Permian and con- 

 tinued into the Triassic ; and the same was true for southwestern Africa, and 

 the southern continent, Australia. The fact that one of the world's hemi- 

 spheres was not concurrent in its geological movements with the other, 

 mentioned on page 406, is here exemplified. It has afforded some strength 

 to the argument that the Permian period should not be united to the 

 Carboniferous. But the distinctions that exist can be recognized and ap- 

 preciated for lands about the Indian Ocean, without interfering with the 

 chronological subdivisions which best accord with the facts in the others 

 where these subdivisions were first laid down. 



