128 ROMER’S DESCRIPTION OF THE CHALK 
This description answers likewise for the plaener* of the 
North of Germany, where it appears generally as a more indu- 
rated chalky marl or limestone, seldom quite white, often some- 
what grayish, sometimes reddish or greenish,—which is deci- 
dedly stratified, and much divided by fissures, and in the lowest 
strata gradually acquires more clay and silica, and oxide of iron, 
accompanied by a change of colour. Analysis gave 
For the gray marl (plener) 
For the white chalk marl (plener) of the Kromsberg. PR NE Ho 
dee de el a a dees  UUaG 0°050 
Carbonate oflime ... . . O°865 0°855 
See ies ints ele. ee, eC ORS 0060 
IS in Me ase) es O20 0°010 
Oxide of iron (eisen oxyd). . . 0°020 0°020 
Magnesia and oxide of manganese 0°000 0°005 
The greatest thickness of this division of the chalk formation 
is estimated in England at 200 feet ; but in several of the Ger- 
man localities, e. g. at Langelsheim in the Hartz and at Alfeld, 
it increases to 1000 feet, and even more. 
The most westerly deposit of the planer is observed at Essen 
on the Ruhr; where, especially in the neighbourhood of the town, 
it overlies the Hils-conglomerate in inconsiderable thickness ; 
from this place it may be traced, by Bochum, to Padeborn, 
thence by Bielefeld, Iburg, to Grass near Ahaus. At Bochum 
it consists of a soft yellowish-white to bluish-gray chalk marl, 
containing Inoceramus mytiliides and Ammonites varians. To 
the east it becomes harder, and gradually acquires the appear- 
ance of the ordinary. (plener) gray chalk-marl. 
Another considerable tract occupied by this rock extends in 
the valley of the Leine from Winzenburg across Sack and 
Wrisbergholzen to Gronau. It occurs also at Calenberg, at 
Hulfersberg near Sarstedt, at Kromsberg on the south-east of 
Hanover, at Gross Solchen near Peine, between Wohlde and 
Wolfenbuttel, in the vale of Innersten, between Wartjenstedt 
and Liebenburg; quite on the north border of the Hartz moun- 
tains from Lutter at Barenberg, to Quedlinburg at Halberstadt ; 
in Saxony near Weinbohla, Strehlen and Oberau; in the north 
* Some of the identifications mentioned in this paper, of the German sub- 
divisions of the chalk series, with those of England, appearing to be attended 
with doubt, it has been thought expedient to insert here both the German 
and English names : as of the flammen-mergel, plener, and quader.—Trans. 
