FORMATION OF NORTHERN GERMANY. 149 
Still more considerable masses belonging to the chalk forma- 
tion occur between the Leine and the Elbe. In the first place, 
close to the Leine, between Gronau and Vincentburg, the chalk- 
marl (plzner), banded marl (Flammen-mergel), and lower green- 
sand (quader), form a considerable range of mountains,—the 
Siebenberge, the Sackwald, &c.; and the first two of these de- 
posits, especially the plzner and Flammen-mergel, are here very 
strongly developed. The lower greensand appears to rest at this 
place immediately upon the Dogger (lias clay), and is but little 
raised. 
At Sarstedt we observe, on the Hulfersberg, the same deposits, 
gray chalk (plener), and banded marl (Flammen-mergel), in- 
clining northwards; and some hundred paces to the south, appa- 
rently the gault also, with Hamites compressus. The same moun- 
tain range continues behind Algermissen to Solschen ; the lower 
plener (gray chalk), forms to the north of it the heights at 
Rethen, the upper gray chalk (Ober-plener), the Kronsberg ; 
the lower chalk marl occupies, without appearance of disturbance, 
the district between Ilten and Ahlten, between Oberg and Ga- 
denstedt, that of Schwicheldt, Meerdorf and Dudenstedt, every- 
where abounding in fossils. 
Near Hildesheim the Hils-clay is deposited on the northern 
foot of the upper Jura, and strikes over Achtum, Wendhau- 
sen and Farmsen to Lafferde; the lower greensand rests upon it 
at Ottbergen,—and upon this the pleener (gray chalk), which may 
be traced across Nettlingen and Sehlde as far as Lengede. 
A much more extensive chalk deposit commences at Waitjen- 
stedt and Lutter, on the Barenberg; it appears along the entire 
northern border of the Hartz mountains, and terminates only be- 
yond Blankenburg. The principal mass is formed upon (pleener) 
gray chalk-marl, which rests upon (Flammen-mergel) streaked 
marls, (upper) greensand, (quader) lower greensand, Hils-conglo- 
merate, and Hils-clay ; and, from Goslar to Blankenburg like- 
wise supports considerable masses of the upper and (at Iseburg) 
lower chalk marl. All the strata appear to be strongly elevated 
close to the border of the Hartz, or, as at Goslar, even to be 
thrown backwards; but at some distance they present a much 
smaller inclination. At Quedlinburg this chalk formation forms 
a double trough; one between Thale and Quedlinburg, the other 
between this latter place and Halberstadt. The lower greensand 
however constitutes there the oldest deposit, and appears at 
