FOSSILS OF THE WHITE CHALK. 
293 
been accumulated contemporaneously even in European seas. 
The siliceous sandstone called upper quader ” by the Ger¬ 
mans overlies white argillaceous chalk or planer-kalk,” a 
deposit resembling in composition and organic remains the 
chalk marl of the English series. This sandstone contains 
as many fossil shells common to our white chalk as could be 
expected in a sea-bottom formed of such different materials. 
It sometimes attains a thickness of 600 feet, and, by its 
jointed structure and vertical precipices, plays a conspicu¬ 
ous part in the picturesque scenery of Saxon Switzerland, 
near Dresden, It demonstrates that in the Cretaceous sea, 
as in our.own, distinct mineral deposits were simultaneously 
in progress. The quartzose sandstone alluded to, derived 
from the detritus of the neighboring granite, is absolutely 
devoid of carbonate of lime, yet it was formed at the dis¬ 
tance only of four hundred miles from a sea-bottom now con¬ 
stituting part of France, where the purely calcareous white 
chalk was forming. In the North American continent, on 
the other hand, where the Upper Cretaceous formations are 
so widely developed, true white chalk, in the ordinary sense 
of that term, does not exist. 
Fossils of the White Chalk. — Among the fossils of the 
white chalk, echinoderms are very numerous; and some of 
the genera, like Ananchytes (see Fig. 239), are exclusively 
Fig. 239. 
Ananchytes ovatus, Leske. White chalk, upper and lower. 
a. Side view. b. Base of the shell, on which both the oral and anal apertures are 
placed; the anal being more round, and at the smaller end. 
cretaceous. Among the Crinoidea, the Marsupites (Fig. 242) 
is a characteristic genus. Among the mollusca, the cepha¬ 
lopoda are represented by Ammonites, Baculites (Fig. 229, 
p. 286), and Belemnites (Fig. 226, p. 283). Although there 
are eight or more species of Ammonites and six of them pe¬ 
culiar to it, this genus is much less fully represented than 
in each of the other subdivisions of the Upper Cretaceous 
group. 
Among the brachiopoda in the white chalk, the Terehra- 
tulce are very abundant (see Figs. 243-247). With these 
