THE GEOLOGICAL AGE OP CENTRAL AND WEST CORNWALL. 25 



be described as the Fowey beds ; and that they are unconform- 

 able with both. This would seem to indicate that they are 

 .Devonian, and that the Fowey Beds themselves are Upper 

 Silurian. 



Before concluding my remarks on these post-Silurian beds, I 

 must briefly refer to certain well-known fragmentary deposits 

 which are probably of the same age. 



A trappean conglomerate occurs close to the Nare Head in 

 Grerrans Bay, which encloses large masses of black limestone. 

 Calcareous conglomerates are also known at Porthluney, near 

 Caerhayes, and at Great Peraver, near Gorran Haven. Hitherto 

 no organic remains have been found in the Nare Head fragments, 

 but those at Forth Luney have yielded " joints and stems of 

 encrinites and two sorts of coral,''^ together with orthoceratites 

 precisely similar to those contained in the Gorran limestones ;*' 

 consequently these conglomerates must be newer than the Gorran 

 rocks. 



The Fowey Beds. (Upper Silurian.) 



Since the publication of De la Beche's " Report," the labours 

 of a considerable number of local geologists, and especially 

 those of my venerable friend Mr. C. W. Peach, have brought to 

 light large numbers of fish-remains from Lantivet Bay, Polperro, 

 Looe, and other localities, as well as many brachiopods, encrinites, 

 trilobites, echinoderms, and corals. These, however, are for the 

 most part either of species which cannot be recognised as 

 occurring elsewhere, or such as may be common to Devonian 

 and Silurian strata. Mr. Eay-Lankester took up the study 

 of the fish-remains of Lantivet Bay some twenty years 

 since, and soon succeeded in showing that they were really 

 remains of fishes, and not sponges {steganodicUjum) as stated by 

 Mc Coy. Their fragmentary nature, however, seems to have 

 soon disgusted him, and he turned his attention to more promis- 

 ing, if not more profitable, material. He writes me that he 

 found " a species of Pteraspis, and probably also a Cephalaspis, " 

 and believes that " some fish-spines, and a scale like Holoptychius 

 have also been found." 



* On the Geology of part of the parish of Gorran, hy C. W. Peach, Trans. 

 Boy. Geol. Soc. Corn., VI, 237 and 57. 



