402 Geological Society. 



have hastened to place their reasons for doing so upon record, before 

 the Geological Society. On three out of four of the essential 

 points in their former communication, the authors' views remain 

 'unchanged ; they adhere to the belief, which they were the first to 

 put forth, that the greater portion of Devonshire belongs to the true 

 carboniferous system, and that the succession and lithological cha- 

 racters of the different mineral masses in North and South Devon, 

 which they then pointed out, remain unaltered. In proof of this 

 there w^ere suspended, during the reading of the paper, the same 

 sections as were exhibited at Bristol in 1836. The change, there- 

 fore, which they propose, is to remove the lowest rocks from the 

 Cambrian and Silurian systems to the old red ; and their reason for 

 making this alteration is founded on zoological evidence recently 

 obtained, which shows that the organic remains of these deposits 

 are of a peculiar character, approaching in the upper division, the 

 fossils of the carboniferous strata, and in the lower, those of the Si- 

 lurian system ; as well as upon the previously ascertained regular 

 sequence or passage from the carboniferous strata, through all the 

 subjacent series of deposits. 



The fossil plants of the culm basin having been formerly deter- 

 mined to be, as far as recognizable, true coal measures remains, and 

 the deposit having been therefore assigned to the era of the carbo- 

 niferous system, the order of superposition being also clear, the 

 strata underlying the coal basin might naturally be referred to 

 the old red sandstone, if the organic remains found in them, belonged 

 to a natural group, intermediate between the fossils of the carboni- 

 ferous and Silurian systems. Subsequent examination has proved 

 that such is the case ,• but this distinction could not have been ascer- 

 tained had not Mr. Murchison published his work on the Silurian 

 system. 



In the order of sequence there is now no difference of opinion 

 between the authors and Mr. De la Beche and Mr, Wilhams, the 

 only point on which the agreement is not common, being the class 

 to which the formations should be assigned. 



The authors then explained that their sections both in S. Devon 

 and N. Cornwall indicate, with some hmited exceptions, a passage 

 downwards, the transition being stratigraphically true, whether the 

 beds be examined along the banks of the Taw, near Barnstaple, on 

 the north, or to the west of Launceston, on the south of the great 

 trough. 



The authors next gave an approximate list of the fossils, collected 

 by themselves or placed at their disposal by the Rev. R. Hennah, 

 Major Harding, and the Rev. D. Wilhams, referring them to the 

 great mineral groups to which they belong, both in North and 

 South Devon. 



Descending order in North Devon. — The shells in the uppermost 

 group, beneath the culm, as at Barnstaple, in the North of Devon, 

 and South Petheiwin, near Launceston in the south, approach ge- 

 nerally forms of the carboniferous system, consisting of Goniatites 

 of new species, and of spined Product! and Spirifers, entirely unlike 



