182 THE GEOLOGICAL AGE OP OENTEAL AND WEST CORNWALL. 



10. Calymene parvifrons. A specimeu from Great Peraver is in 

 the Museum at Jermyn Street, and is called Loiver 

 Llandeilo by Murcliison. Salter says the Cornish speci- 

 men is var. Miirchisonii, and that the whole genus is 

 characteristic not only of the Lower Llandeilo flags but 

 also of the Arenig, Stiper Stones, and SMddaw Slates. 



C. Sternbergii of Peach and Murchison, 1846, is discarded by 



Murchison in 1867, and not mentioned as a Cornish 



species by Salter. 

 C. Senex from Grorran Haven is also mentioned in early writings, 



but discarded by Salter. There is still, however, a 



specimen so marked in Jermyn Street. 

 Thus of the 10 species of Trilobites found in the quarfczytes, 

 9 are said by Salter to be undoubtedly of Llandeilo age, most of 

 them are Lower Llandeilo, while 2 — C. Tristani and C. parvifrons 

 — are found in the horizon of the Arenig and Skiddaw Slates. 

 Murchison himself in the 5th Ed. of his "Siluria," 1872, 

 gives 5 of these species as Llandeilo. As regards C. Blumenhachii 

 we have already said that it is a species of very wide range — 

 from CaradoG to Upper Ludloio — and therefore it need not at all 

 surprise us to find it in Llandeilo or even somewhat older rocks 

 — more especially since its geographical range is as conspicuously 

 wide as its range in time. The evidence of the trilobites, 

 therefore, is that the rocks are at least as old as the Llandeilo 

 flags, and perhaps older. 



BRAOHIOPODA. 



(See Davidson Pal. Soc, 1881.) 



1. Strophomena grandis. This has been met with at Q-orran 



and Caerhayes. It occurs in the Budleigh-Salterton 

 conglomerate, in pebbles of dark-grey or greenish 

 ferruginous rock, often with Ortliis calligramma and 

 0. scotica. (Davidson, Pal. Soc, 1881, PL xlii supp., 

 where it is figured. It is figured also in Murchison' s 

 " Siluria," where it is given as a characteristic Caradoc 

 species). Specimens named by Mr. Davidson may be 

 seen in the Museum at Penzance. 



2. Ortliis calligramma. This is found at Grerrans Bay, Gorran 



and Caerhayes, and also in the Budleigh-Salterton beds 

 (v. remark on Stroph. grandis above.) Its range is, 



