142 ROMER’S DESCRIPTION OF THE CHALK 
Terebratula depressa. Spondylus striatus. 
Ostrea macroptera. Thetis Sowerbii. 
Pecten atavus. Serpula angulosa. 
There also occurs in it, at Essen, a small Balanus. 
3. Hils-clay:—-Speeton clay. [Der Hils-thon.] 
At the northern foot of the Deister, at Bredenbeck and Wen- 
nigsen, is situated, immediately upon Weald-clay, another grayish- 
blue argillaceous mass, about 60 feet thick, which contains nu- 
merous roundish nodules of a grayish-brown compact limestone, 
knobs of iron pyrites and small crystals of gypsum. This is the 
Hils-clay. 
It occurs with the same character on the northern foot of the 
Galgenberg at Hildesheim; especially at the villages Achtum 
and Wendhausen, and is continued at Farinsen and Laffarde. 
A third and better known locality is in the Hils-mulde* (the 
“trough of Hils”), close to Alfeld. This argillaceous mass is 
here met with nearly everywhere beneath the quader; and is, 
especially at Elligserbrink, where formerly a seam of ironstone, 
4 inches in thickness, was worked, a well-known and rich 
locality for fossils. It is likewise exposed on the southern de- 
clivity of the Hils, by several water-courses. In many parts of 
the Hils-mulde, large unstratified masses of a compact spotted 
gypsum occur in it, which at Weenzen frequently contain an ex- 
cretion (ausscheidung) of pure sulphur, with sometimes earthy, 
sometimes slaggy, mountain-pitch. The mineral springs at 
Lauenstein likewise appear to originate in this clay. 
Judging from some of its fossils, the Hils-clay would appear 
to occur at Rehburg, and in the neighbourhood of Salzgitter 
and Liebenburg; where however we have not seen it in person. 
It also appears under perfectly similar relations, under the form 
of a schistose, sometimes white-spotted clay-marl, called Tock, 
in the island of Heligoland, and there affords numerous fossils 
which are mostly converted into iron pyrites. 
In the sand-pit at Goslar is seen, beneath the quader (lower 
greensand), a mass which at the upper part consists of about 2 
* The names of this deposit, and of the Hils-conglomerate, are taken from 
the place here mentioned, of the vicinity of which a map will be found in 
Hoffmann’s Geognoslische Charte vom Nordwestlichen Deutschland, in 24 
plates :—Berlin, 1829. Some other sheets of that valuable map will also be 
found useful in perusing the present translation.—Trans. 
5 ae 
ee Oe a eee eer ene 
