GEOGNOSY AND GEOLOGY. 179 
The cretaceous system is extensively distributed ; it is, found in Denmark, 
England, France, Belgium, Germany, as in Mecklenberg, Lower and 
Upper Saxony, Westphalia, Bohemia, Franconia, and Silesia; it likewise 
occurs in the chain of the Alps and Jura, in the Pyrenees, in Spain, 
Portugal, the Apennines, Sicily, Greece, Hungary, Galicia, Poland, Russia ; 
in Asia, on Mount Lebanon; in Northern and Southern Africa. The 
cretaceous system of North America differs in many features from that of 
Europe. True chalk is entirely wanting, the series being represented by 
greensand, marls, and a shelly limestone often of great compactness. It 
occurs in New Jersey, Maryland, Virginia, North and South Carolina, 
Georgia, Alabama, Arkansas, and various other regions. 
In Germany, the cretaceous extends along the northern sea coast, and 
from Westphalia towards the east; it is very similar in character to the 
French system. 
The lower strata are formed by the Hils clays (bluish clay with hard 
calcareous nodules), which are probably the equivalents of the upper part 
of the Neocomien formation ; upon these rest sandstones, of more or less 
thin stratification, and of different colors of brown and red, with no great 
compactness, even running at times into quite a loose sand bed: these 
appear to correspond to the lower greensand. The strata of the gault are 
not weli recognised in North Germany. The beds corresponding to the 
upper greensand are known in Westphalia as very similar to those in 
England and France; they are, nevertheless, principally replaced by 
flammen marl. Upon these lies the chalk marl, whose hard, marly, grey 
limestone, with alternating layers of clay, closes the highly fossiliferous series 
of the freestone chalk which occurs in such complete development in 
northern Germany on the Island of Rigen. 
The lower chalk is developed in quite a peculiar manner in Saxony : it is 
there represented by masses of a fine-grained white, grey, or yellowish-brown 
quaderstein, whose regular fissures, cutting each other at right angles, form 
the delightful valleys of the Meissner uplands, or the Saxony Switzerland. 
Between the sandstone masses there passes a layer of limestone, readily 
splitting up into plates, known as the planerkalk, and appearing to corre- 
spond to the gault. The subjacent quadersandstone must in this case 
be considered as the equivalent of the lower greensand, and that above it 
as the upper greensand. 
Fossins or THE Creraceous System. The chalk is very rich in fossils ; 
among polyps, a prominent form is Hallirhoa costata ( pl. 39, figs. 1 and 2), 
a spongeoid hard body, with a large aperture in the upper pedunculated and 
often lobed expansion. 
The infusoria play an important part in the chalk, forming entire strata. 
Here belong the Rhizopoda (Foraminifera, Polythalamia), whose almost 
microscopic calcareous test was at an earlier period looked upon as the shell 
of a minute cephalopod, to which it has an unmistakable resemblance 
The shell, which contained a series of minute apertures for the passage of 
the organs of motion, is divided into chambers, which do not communicate 
with each other, each one inhabited by a distinct animal. This fact, 
ICONOGRAPHIC ENCYCLOPADIA.—VOL. I. 39 609 
