1868.] UOLL SOUTH DEVON AND EAST CORNWALL. 453 



rocks, and, with the possible exception of Ilfracombe, arc all on 

 the same horizon. 



The abundance of species of Cyrtoceras at the Woolborough quarry 

 is quite as remarkable as that of species of Clymenia at Land- 

 lake. Of the 13 species jjwhich have been found at Woolborough, 9 

 are peculiar to the locality. One, Cyrtoceras rusticum, occurs like- 

 wise at Landlake, and three species occur in the Middle Devonian 

 rocks of continental Europe. The Tetrabranchial forms, therefore, 

 constitute a colony singularly restricted in range, and in consequence 

 of these and the many other peculiar forms of extinct life asso- 

 ciated at this spot, it has been suggested that this small mass of 

 limestone, which here protrudes through the Culm-measures, may 

 be of a different age from the rest of the Torbay limestones ; and that 

 the Woolborough and Landlake beds may have been synchronous, 

 and referable to the lower part of tlie Upper Devonian series*. 

 Against this view it may be urged that not one of the 13 species of 

 Cyrtoceras, and only one of the 11 species of Clymenia, and one only 

 of the 4 species of Goniatltes met with in one or other of these two 

 localities are known to occur in Upper Devonian rocks in any area. 



But there is another and more fatal objection to this view, inas- 

 much as it assumes the existence of a fault with a downthrow of 

 several thousand feet, and of course of an extent proportionate to 

 such an effect ; whereas there are only a few small faults in the 

 vicinity with a throw of a hundred feet or so, perhaps less ; for the 

 Connator fault, if continuous with that of Bow HiU at all, has the 

 downthrow on the other side, towards Ogwell and Ipplepen, or what 

 amounts to the same thing, an upcast on the east, i. e. on the Wool- 

 borough side. 



No further than Marldon, a few miles to the south, we see the 

 Torbay limestones overlain by a great thickness of red slates and 

 grits almost devoid of fossils ; and the character of the rocks which 

 overlie the upper limestones of South Devon is further seen in the 

 succession of beds southward of Brixham, where they attain a thick- 

 ness of several thousand feet ; and there are not, and cannot be, any 

 such faults as would cut out this great mass of red rocks and bring 

 yet higher beds down among the Torbay limestones without pro- 

 ducing more obvious effects than are visible on the country through 

 which it passed. 



The identification of the Steganodictyum Cornuhicum, M'Coy, 

 with the genus Pterasjois by the Bev. W. S. Symonds, of Pendock, 

 which has since been confirmed by Prof. Huxley, has an important 

 bearing upon the question of the age of the rocks of South Devon and 

 Cornwall ; for although it affords us no further aid by which to co- 

 ordinate these rocks with any particular portion of the Old Bed 

 system, either of the Silurian area or of Scotland, the species being 

 specifically different from any at present known in the Old Bed, it 

 throws additional weight on the views of those geologists who hold 

 the two systems to be equivalent in time. The species is somewhat 

 widely distributed ; and I learn from Mr. Pengelly that it occurs at 

 * Salter, Quart. Journal Gcol. S'oc. vol. xix. p. 483, footnote. 



