WEAVER: INVERTEBRATE PALEONTOLOGY AND HISTORICAL GEOLOGY 593 



more important of these investigations were those of C. F. Roemer (1844) on the 

 faunas and stratigraphy of the Silurian and Devonian rocks of the Rhineland. 



The classification of the less deformed upper Paleozoic rocks in Great Britain 

 into Old Red Sandstone, Carboniferous Limestone, Millstone, Grit, and Shales, 

 and Coal Measures earlier in the century had been established by Conybeare 

 and Phillips and named the Carboniferous system. The geographical extension 

 of these limestones into Belgium afforded an opportunity for an intensive study 

 of the faunas by de Koninck in 1844. The occurrence of similar limestones in 

 the eastern Alps was noted by von Buch in 1824. The uppermost Paleozoic rocks 

 in Germany were termed the Zechstein and consist of a succession of shales, 

 sandstones, and conglomerates which pass upwards into limestone, dolomite, and 

 marl. These rocks which underlie the Triassic were investigated early in the 

 nineteenth century and the Zechstein group was considered as equivalent in age 

 to the Magnesian Limestone of England. The rocks of late Paleozoic age in the 

 Ural Mountains of Russia had been studied by several geologists and the result- 

 ing published maps drew attention to this area as worthy of special investiga- 

 tion. Accordingly, Murchison, who already had examined many areas in the 

 Alps and other parts of Europe, was requested by the Russian government to 

 make a geological study of the Province of Perm. He was accompanied by the 

 French geologist, de Verneuil, and the Russian Count, von Keyserling. The 

 results of this investigation were published in 1845 in their monograph. The 

 Geology of Russia in Europe and the Ural Mountains. The rocks which overlie 

 the coal-bearing beds were called the Permian system. 



The marked variations in the lithologic character of the faunal facies of 

 the Cretaceous rocks in different parts of Europe in contrast to the greater uni- 

 formity prevailing among the Jurassic resulted in the development of several 

 distinct forms of classification and nomenclature. Numerous important contri- 

 butions were published before the middle of the nineteenth century and the 

 succession of formations in each country was fairly well established. By 1850 

 the broad outlines of the stratigraphical and faunal classification of the Creta- 

 ceous deposits were somewhat similar to those in use at the present time and 

 served as a foundation for more detailed research in other parts of the world 

 from 1850 to 1950. 



In England the sedimentary rocks lying between the basal Tertiary and 

 Upper Jurassic were classified by William Smith in downward sequence as the 

 White Chalk, Gray Chalk, Greensand, and Micaceous Clay. Certain dark claj'-s 

 occurring locally beneath the Greensand were called the Blue Clay but were 

 later designated the Gault. Later investigations by Fitton in eastern Sussex 

 showed that a portion of the lower Greensand passed from a marine to fluvia- 

 tile facies. This was termed the Wealden formation. These deposits contain a 

 rich flora and the remains of fossil reptiles. The name Speeton clay was given to 

 beds in Yorkshire equivalent to the lower Greensand. The Upper Cretaceous or 

 White Chalk was recognized as extending eastward into Belgium, France, Den- 

 mark, North Germany, and Poland. 



The Cretaceous stratigraphic and faunal units of Great Britain are widely 

 represented in France but the complete sequence of beds is not everywhere pres- 

 ent. There is a prevailing similarity of the upper White Chalk and marls but the 

 middle and lower members often present marked differences in litliology. Early 



