TRANSACTIONS OF THE SECTIONS. 
61 
parallel of these masses in Skiddaw Forest, the Professor did not de¬ 
termine. 
Professor Sedgwick explained the mode of connecting Mr. Mur¬ 
chison’s researches with his own, so as to form one general system. 
He pointed out also the limit, as at present known, of fossils, none 
having been hitherto discovered in the Lower Cambrian schists, and 
remarked in reviewing the general phenomena, that geological epochs 
were not effected by shocks, but, like everything in nature, were 
under the dominion of the usual laws of causation. 
Notices of the Geology of Spain. By Dr. Traill. 
The author gave a sketch of the results of his personal researches 
in the geology of Spain, restricting himself, however, to a few only 
of the more striking peculiarities. He stated that it was an error to 
suppose all the mountain chains of Spain branches of the Pyrenees, 
from which they are in many cases completely separated. The va¬ 
riety of climate, and circumstances produced by the union of these 
mountains with the elevated table lands of New Castile, which is two 
thousand feet, and of Arragon, which is two thousand five hundred 
feet above the sea, had very peculiar effects on the flora of the coun¬ 
try. Dr. Traill pointed out the identity of character which existed be¬ 
tween the granites and schists of Spain and England, and proceeded 
to the newer strata; described the brine springs and salt lakes of 
Andalusia, and the deposit of salt which forms part of the base of 
the plain of Grenada. He also showed that lias and true chalk, with 
layers of flint, occur in the South of Spain, and confirmed the state¬ 
ments by Colonel Silvertop, of the tertiary deposits of Spain. Dr. 
Traill further observed, that bones are found in the fissures of other 
hills in Spain besides that of Gibraltar. 
On certain Disturbances in the Coal Strata of Yorkshire having a 
remarkable Delation to existing ’ Valleys ; illustrated by a Map and 
Sections. By Henry Hartop. 
M. Agassiz presented the fourth and fifth livraisons of his 
work on Fossil Fishes, and stated, that by the great addition of 300 
species which had been obtained from the cabinets of these countries, 
the total number had been raised to about 900. He then advanced 
some general views on the conclusions to be drawn from the geolo¬ 
gical distribution of fishes, and explained the precision in determining 
epochs which their higher state of organization and consequent 
susceptibility to external influences afforded. The fishes of the car¬ 
boniferous period were different from those of the lias ; the fishes of 
the lias different from those of the oolite; and those of the oolite 
from the fishes of the chalk: and as it must be presumed that fishes 
living together so coexist from the necessity of their organization, 
and its adaptation to attendant circumstances, it must also be pre¬ 
sumed that their disappearance was the result of a change in the 
