CARBONACEOUS STRATA OF CORNWALL, 
541 
right to consider such a disposition uni- 
versal — Mr. Sedgwick remarked, that 
he could with certainty distinguish four 
calcareous strata in North Devon — viz. 
one at Linton, a second at Ilfracombe, 
and two others at Barnstaple. The dif- 
ference of the limestones of South De- 
von was also very remarkable ; that of 
Plymouth being essentially distinct 
from that of Dartmoor. These carbo- 
naceous strata also extended several 
miles into Cornwall. — Mr. Conybeare 
considered that the public had exagge- 
rated the difference of opinion then be- 
fore the meeting. He was rather inclin- 
ed to coincide with Messrs. Sedgwick 
and Murchison in considering the strata 
in dispute as referable to the general 
carboniferous system, and from the ge- 
neral resemblance of the formations of 
those of Pembrokeshire, the probability 
was much strengthened. — Professor 
Phillips conceived that it had been satis- 
factorily proved, that there existed a 
coal basin in the interior of Devonshire, 
although, at first sight, from the unpro- 
fitable nature of the contained coal, be- 
ing the kind called Culm, some hesita- 
tion might have taken place as to assign- 
ing it its true position. But doubts 
must vanish on inspecting the organic 
remains: and here he might observe, 
that it was a mistake to suppose that Dr. 
Smith, the founder of English Geology, 
had ever intended to limit the range of 
these remains as some had accused him 
of. We might readily assume, and ob- 
servation has confirmed, that some or- 
ganic remains of one stratum may be 
found in contiguous strata, associated 
with fossils of different kinds, so that 
organic remains alone are insufficient to 
point out distinctions in strata. But, 
the general appearance of the limestones 
of Devon was precisely similar to those 
of the north of England, in regard both 
to mineral character and imbedded fos- 
sils. From their appearance, he had 
expected their interstratification with 
shales, and Mr. Murchison had confirm- 
ed this supposition. The Devon lime- 
stone corresponded indeed with the up- 
per bed of the Yorkshire limestone ; in 
the^ former he had detected a shell, a 
species of Anodon, which he had not 
observed in the latter : but the species 
of Posidonia found in both exactly cor- 
respond. Perhaps one cause of mis- 
take might have been the little attention 
paid to the black limestone of Craven, 
by Mr. Conybeare, and to this lime- 
stone there was a most striking resem- 
blance in the black variety of Devon- 
shire. He alluded to the extraordinary 
anomaly of coal plants having been 
found in the Alps, associated with ooli- 
tes, but this might be an exception from 
the general law, and exceptions there 
must be ; still it must be allowed, that 
organic life must have a constant rela- 
tion to the state of the actual surface. 
He came to the conclusion, that the 
Devon district would not offer any 
anomaly in geological arrangement, 
but that it would correspond in ar- 
rangement with the other parts of the 
country, and that a fruitful source 
of error is the hitherto vague term 
Greywacke, which has been applied 
indiscriminately to a great variety of 
rocks, so as to include many of different 
ages throughout this country. — Dr. 
Buckland congratulated the meeting on 
the difference of opinion among the geo- 
logists present, such a difference produ- 
cing discussion, which was the sure 
means of arriving at truth. He con- 
sidered, that the true solution of the 
question at issue would be in the middle 
course ; that, no doubt, it could not be 
easily granted, that the series under con- 
sideration was carboniferous, when no 
true coal was contained in it ; but, were 
we to adopt the new term culmiferous, 
we should get rid of the difficuty. This 
culmiferous series he regarded as the 
lowest portion of the coal formation, and 
as resting upon the Silurian rocks. He 
alluded to the difficulty of making theo- 
logical maps ; these must be constantly 
modified, according to extent of investi- 
gation : errors of omis.sion must be 
committed by every pioneer in Geology, 
which can only be corrected by the 
researches of succeeding observers. 
After the discussion was closed, Mr, 
De la Beche rose to submit some consi- 
derations on the connexion of the Geolo- 
gical Phenomena of Cornwall and Devon 
with the Mineral Veins of those coun- 
ties. He commenced with defining the 
local Cornish terms of lode, cross course, 
counter, and elvan, the first three refer- 
ring to veins of metallic, the latter to a 
vein of granitic matter. A number of 
these had been laid down in his geological 
map of Cornwall with the most perfect 
mathematical accuracy. He next men- 
tioned the overlying masses of green- 
stone, which are of different age, and ijj 
