J. B. Hill — The Palceozoics of West Cornwall. 211 



•conglomerate and the more advanced type of deformation represented 

 by the adjoining Portscatho and Veryan divisions. Mr. John 

 Pringle has obtained numerous plant remains from these rocks, 

 together with a few corals and brachiopods, but beyond indicating 

 a marine fauna they throw no light on their geological age. The 

 argillaceous members were searched for graptolites, but without 

 success. 



The Manaccan Series is also characterized by the presence of 

 a basic lava that occupies a well-marked horizon between Koskruge 

 and Tregidden. Its contemporaneous nature is clear, not only from 

 its having been involved with the coarser deposits, and frequently 

 partaking of a conglomeratic margin, but scoriaceous boulders 

 clearly derived from it have been incorporated with the adjacent 

 conglomerate. The rock is a very fine-grained basalt, often 

 andesitic, and belongs to the 'pillow lava' class. As this rock is the 

 sole greenstone in West Cornwall that can be definitely separated 

 from the intrusives, it is possible that the contemporaneous green- 

 stones are restricted to the Devonian.^ Moreover, its comparatively 

 undeformed condition still further illustrates the less advanced 

 metamorphism presented by the Devonian rocks to that of the 

 Lower Palceozoics. 



Tlie Veryan Series of Meneage. — The quartzite is almost entirely 

 hidden beneath the Manaccan Series, throug-h which it emerg^es in 

 numerous lenticles from Penare on the east to Trevaddra on the 

 west. Besides being veined with quartz it is often extremely 

 brecciated, but in this condition loses nothing in compactness, the 

 interstices being filled up with silica. This character was attained 

 prior to the formation of the overlying conglomerate. 



The Veryan Series is exposed along the coast from a little north 

 of Nare Cove to Porthallow Cove, whence it extends inland as far 

 as Treglossack, and is there overlain by the Manaccan Series. This 

 small tract is highly disturbed, while local thrusts and brecciation 

 with production of pseudo-conglomerate are prevalent, and it is, 

 moreover, not solely confined to the Veryan group. The quartzite 

 appears between Nelly's Cove and Porthallow Cove. Thin limestones 

 are seen from Nelly's Cove to Nare Cove. Eadiolarian cherts are 

 distributed over the section, and are strongly developed at Nelly's 

 Cove. The Portscatho Series and strips of the overlying conglomerate 

 can also be detected, more especially at the south of Porthallow Cove, 

 where the former is contiguous to the Lizard group. It is probable 

 also that this highly disturbed tract may contain representatives of 

 other zones,^ but the Veryan Series undoubtedly preponderates. At 

 Gallentreath, between Nelly's Cove and Porthallow Cove, a green- 

 stone of pillow lava type is seen that recalls the pillow lava of 

 Mullion Island. Another highly silicified igneous rock that is 

 •closely adjacent resembles a similar band mapped by Mr. Eeid 

 at Perhaver. Like the rock at Mullion Island, the Gallentreath 



1 The evidence pointing to the Devonian age of the Manaccan Series will follow. 

 - Geol. Mag., 1904, No. 481, in which Mr. C. D. Sherborn has referred fossils 

 obtained from this district to Ludlow age. 



