2 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [NoV. 5, 



It is well known to all wlio take any part in' the working of onr 

 Society, that during the past year Sir R. I. Murchison, after an 

 examination of certain fossils sent to him from Cornwall, has intro- 

 duced some new colours into the geological maps of Cornwall and 

 South Devon*. Thus, he colours the great headlands, between 

 the Bays of St. Austell and Falmouth, Lower Silurian. Again, he 

 colours a considerable part of the coast in the neighbourhood of 

 Looe, &c.. Upper Silurian ; and the same colour is extended to a 

 portion of the slates of South Devon which skirt the north side of 

 the metamorphic rocks of Bolt Head and Start Point. The first 

 change of colour is grounded on good evidence ; for in the great 

 headlands S.W. of Austell Bay there is a development of rocks with 

 a remarkable mineral structure, and with fossils which I should call 

 Cambrian, and which Sir R. I. Murchison calls Lower Silurian. If 

 I mistake not, there is, however, rather too great an extension given 

 to the new colour in this part of the map of Cornwall. As to the 

 Upper Silurian colour, it was put in hypothetically, or on imperfect 

 evidence ; and I believe, that both from Devonshire and from Corn- 

 wall it must be expunged as erroneous. 



During my short tour in Cornwall, Professor M'Coy was my fellow- 

 labourer. Before we started on our tour he had come to the con- 

 clusion, that many of the dark-coloured fossils, derived from the 

 Cornish coast near Fowey, Polperro, and Looe, were not the remains 

 of Fishes, but portions of Sponges. It was after a very careful mi- 

 croscopic examination (in which he was assisted by Mr. Carter of 

 Cambridge) of specimens partly collected by myself in 1836, and 

 partly procured from Mr. Peach, that Professor M'Coy had come to 

 this conclusion ; and during the past summer it has not been invali- 

 dated, but greatly confirmed, by an inspection of the Cornish speci- 

 mens in the London Museum of Practical Geology, as well as those 

 we afterwards collected during our tour, or found in the public and 

 private collections of Cornwall. All evidence for the existence of 

 Upper Silurian rocks in Cornwall, derived from fossil Fishes, seems to 

 be done away, and the same remark applies to other supposed 

 Upper Silurian fossils f. 



When Sir R. I. Murchison and myself commenced our examination 

 of Devonshire in 1836, our first and main object was to determine 

 the true position of the culmiferous beds which were known to con- 

 tain many common Carboniferous fossils. After making traverses 

 from the north to the south shores of the county, and after using 

 all other means in our power, we came to the conclusion that the 

 Culm-system of North Devon was deposited in a trough superior to 

 all the other palaeozoic rocks, and that it was overlaid by no rock older 

 than the New-red-sandstone ; and hence, that this system (as there 



* See Geological Map of England, published by the Soc. Diffus. Useful Know- 

 ledge. See also Trans. R. Geol. Soc. Cornwall, vol. vi. p. 317 et seq. 



t After my return from South Wales in 1846, Professor M'Coy proved, in like 

 manner, by microscopic examination, that certain supposed fragments of Fish- 

 bones from the Llandeilo Flags had been erroneously determined. See also Quart. 

 Journ. Geol. Soc. vol. vii. p. 264. 



