s 
greater or lesser proportion they contain of such plants as 
yield the largest amount of combustible matter. This sup- 
position, I much regret, it has not been in my power to verify 
from actual examination of all the coals just enumerated. 
In the Middleton coal, which has come more immediately 
under my observation, I have recognized Stigmaria, Favu- 
laria, and Lepidodendron ; and in the museum of this 
society are several very perfect examples of Favularia in 
solid coal whose locality is not recorded. This point, 
however, which I have thus been unable to accomplish for 
our own district, has, I rejoice to find, been most ably and 
conclusively demonstrated by the researches of Professor 
Goeppert, of Breslau, in the coal-fields of Upper and 
Lower Silesia, from whence four millions of tons are 
annually raised. Here he met with extensive layers or 
seams of coal, in which were plants so well preserved, 
of Sigillaria, Stigmaria, Calamites, Lepidodendron, and 
Noggerathia ; and that, according to the predominance 
of one or the other genus of plants, he could distinguish 
in many places coal of Sigillaria from Araucarian or 
Lepidodendron coal, of which the last was the rarest.* 
Subsequently he examined the coal strata of Saarbruck, 
near Aix-la-Chapelle, in Liege, and in Westphalia, and in 
each locality found exactly as in Silesia, though not in such 
perfection, that the coal itself contained plants visible with 
the naked eye ; and in addition to those mentioned above, in 
a pit at Norheim, near Kreuznach, for the first time, a fern, 
Cyatheites arborescens, together with so many Calamites 
belonging to the species known as Calamites decoratus, that 
he thought himself justified in designating it Calamite coal.f 
From his investigation of the Flora of the brown coal 
formation also, it appears that this is almost solely derived 
* Report of the British Association, 1846, p. 50. 
t Quarterly Journal of the Geological Society, vol. v., p. 17. 
VOL. III. A 2 
