352 Proceedings of the British Association. 
many places destitute of any trace of coal, still these beds do not 
differ from the great unproductive coal-field of Pembrokeshire. The 
authors consequently concluded, that from the order of superposi- 
tion,—from mineral structure—from absence of slaty cleavage pecu- 
liar to the older rocks on which this deposit rests, and from the spe- 
cific character of its organic remains, it may without hesitation be 
referred to the regular carboniferous series. In the course of the 
details, the authors alluded toa remarkable elevated beach, occupy- 
ing two miles of coast on the north side of Barnstaple Bay, a more 
special account of which is being prepared for the Geological Society. 
M. De la Beche objected to the conclusions of Messrs. Sedg- 
wick and Murchison, although he did not dispute the correctness of 
the section of the country which they had exhibited to the meeting. 
He conceived that he had traced the carbonaceous rocks passing 
into what had been termed the Cambrian system, although he was 
not prepared to say that it really was that system. He was also 
unable to make that separation of the contorted rocks, suggested by 
the authors of the paper. He spoke of the overlying greenstones 
in different places, and considered that these were of different ages ; 
also of the changes produced by granite on rocks of every kind in 
contact with it. He alluded to the former opinions of the rocks 
called by the general name, Greywacke, which opinions have, of 
late years, been totally altered. He attached very little importance 
to mineral characters: unless the consideration of the imbedded or- 
ganic remains was made of the first importance, we were sure of 
falling into error. Are the organic remains in these carbonaceous 
rocks of Devon really the same as those of the general carbonifer- 
ous system? He stated, that he conceived there was evidence to 
prove that there was a regular band of rocks surrounding Dartmoor, 
which had been thrust up through the hollow in the middle. He 
could nowhere discover any line of separation between the carbo- 
naceous and the older rocks, so that he was unable to reconcile the 
deposits of coal with those of other parts of England, and as to the 
age of these older rocks all were agreed. In the Alps, organic re- 
mains of the coal formation are found in beds, alternating with 
oolites, so that we must not limit too strictly the range of these or- 
ganic remains, as we should be certain of all the conditions under 
which coal plants can be accumulated. We should recollect, that 
the remains of the vegetation of a mountain may be entombed at 
its base, so as to be shifted from its original habitat; and that, although 
