FORMATION OF NORTHERN GERMANY. 127 
above or downwards. It may appear surprising that no distinct 
superposition of the upper chalk upon the lower has been seen 
anywhere in our district, but this is without doubt owing to the 
former being found almost everywhere deposited horizontally 
and in ridges of low hills; at Sudmerberg near Goslar, for in- 
stance, the lower layers which contain numerous Scyphie and 
Siphonia, may perhaps be considered as actually equivalents to 
the lower chalk. We have nowhere met with the lower chalk 
to the east of the Hartz mountains. 
The following fossils are widely distributed and confined to 
the lower chalk :— 
Pleurostoma lacunosum. Cceloptychium sulciferum. 
ea radiatum. Avicula ccerulescens. 
Scyphia Oeynhausii. Arca furcifera. 
-»- Murchisonii. ... tenuistriata. 
... Coscinopora. Pholadomya umbonata. 
Celoptychium agaricéides. Delphinula tricarinata. 
nae lobatum. Pyrula planulata. 
The following species appear to be confined to the upper and 
lower chalk :— 
Grypheea vesicularis. Baculites Faujasii. 
Ostrea flabelliformis. eee anceps. 
Lima semisulcata. Crania Parisiensis. 
Hamites intermedius. --- costata, &c. 
If we add to these facts the scarcity of Ammonites, the occur- 
rence of large variegated Scaphites, and the presence of two easily 
distinguishable Belemnites, it will seldom be difficult to deter- 
mine, from the fossils, whether a sandy formation should be 
referred to the formations just mentioned, or to the still lower 
divisions of the chalk series which we are about to describe. 
II. Gray Cuarx Maru:—Gray Chalk*, [Der Plaener.— 
Kreide-mergel, Wald kalk, Binde kalk, Helmstein.—Craie 
Tuffeau, craie grossiére. | 
The gray chalk-marl (plener) is described in England as a soft 
friable marl, light gray, passing into brown, frequently coloured 
by peroxide of iron, but which sometimes alternates with harder 
seams, and gradually passes downwards into the upper green- 
sand, 
* See note in the following page. 
