95 
Prussia. This specimen was from Westphalia, and is report- 
ed to contain 72 per cent. of Carbon, and 22 per cent. of 
Oxygen, with a very little Hydrogen, but it would seem, 
judging from its light color, that this estimate of the quantity 
of Carbon present is too high, unless it occurs united with 
other substances, so as to make up light-tinted compounds. 
We know that the carboniferous age, and that in which the 
copper-slates were deposited, are very far apart from each 
other, particularly the epoch of the Prussian Copper-slates, 
in which this species of fish, (Hsox Jslebiensis,) and this species 
only, is so abundant. At the time he (Dr. F.) visited this 
locality, in 1827, during a very short period of exploration, 
he had gathered a large number of these Ichthyolites, in fact 
as many as he could conveniently transport. Almost every 
specimen of the material examined, contained one or more 
of these impressions, showing how extremely abundant they 
are at that point. 
The Brown Coal or Lignite is a true Coal, and is very 
unlike the Gagates, our Jet, which is described by Dioscorides, 
and is thought by some to be a hardened bitumen. In 
England and elsewhere it is considerably worked up into 
ornaments and jewelry. ‘The Lignite formation is very 
abundant in various parts of Hurope and in our own country, 
as Texas and elsewhere in the West, where Tertiary beds of: 
the same material occur covering considerable districts. 
The President remarked on the beauty of the specimen, 
exhibited by Dr. Feuchtwanger, and stated that it was eyi-. 
dently from the stratum which is known as the “ Paper-Coal” 
of the Rhine, which belongs to a late part of the Tertiary. 
This name, in German Papierkohl, has been bestowed on 
certain layers of the Tertiary Lignites, from their papery or 
leaf-lke composition and fracture. On examination it is. 
plainly to be seen that it is made up of masses of compressed; 
leaves. In fact, in the fresh state, the venation of the leaves: 
composing it can be made out. 
Lignite, as usually understood, having its name derived 
from the Latin name for wood, lignum, is really fossil wood, 
and often exhibits woody structure in a very beautiful man- 
