208 J. B. Hill— The Palceozoics of West CormcaU. 



a deep buff colour. The material is of finer texture than the 

 Portscatho Beds, and the coarse structure often seen in the latter* 

 is not represented. The presence of zones of strongly contrasted 

 purple and green slate is likewise a distinctive characteristic of this 

 group. 



Mijlor Series. — This division consists of blue argillaceous and 

 fine-textui"ed sandy beds. The latter ai'e often very siliceous, and 

 occasionally thin quartzites are developed. The most distinguishing 

 feature of this series is its striped and ribbon-like appearance, due 

 to fine alternations of siliceous and argillaceous material, or to 

 argillaceous laminae varying in composition and colour. This 

 composite structure, wliile a marked characteristic of this division, 

 is frequently developed both in the Portscatho and Falmouth 

 divisions. In this series it has often contributed to the production 

 of pseudo-conglomerates, following conditions of stress.^ 



Natin-al sequence of the Lower Palaozoic divisions. 

 The four divisions already referred to pass uninterruptedly into one 

 another without any stratigraphical break. The junction between 

 the Veryan and Portscatho groups is well exposed at Pendower in 

 Gerrans Bay. Although the two groups there occupy adjoining 

 horizons, and the former are coloured as Silurian and the latter as 

 Devonian in the old map to which attention has been drawn, their 

 natural sequence is demonstrated by the gradual dying out of the 

 Veryan limestones to the west, and which are still represented in 

 an attenuated form within the Portscatho Series, thus serving as 

 a connecting link between the two groups. Not only do the Veryan 

 Series pass uninterruptedly into the Portscatho group, but these 

 latter also graduate imperceptibly into the Falmouth Series, which 

 in their turn merge insensibly into the Mylor Beds. Notwithstanding 

 the comparative absence of palaeontological data the researches of 

 Mr. Howard Fox and Dr. Hinde on the Radiolaria tend to confirm 

 the unbroken sequence of these deposits. The Radiolarian remains 

 have been determined by Dr. Hinde from localities scattered 

 throughout these divisions, but these organisms have not been 

 detected on any known Devonian horizon. Besides Radiolaria, 

 Crinoidal and other fragments are occasionally found in these 

 divisions,- but their occurrence is extremely rare. The quartzite of 

 Carne in Gerrans Bay, which has yielded Caradoc fossils, was 

 included within the Veryan Series, as it appeared to fall naturally 

 into that division.^ The detailed investigation of that area has been 

 subsequently undertaken by Mr. Reid, whose results do not invalidate 

 that sequence. 



Belations of the Newer and Older Faleeozoics in the Manaccan area. 

 Having now given a brief outline of the Lower Palaeozoic 

 divisions, in so far as they have been investigated by the author, 



1 An account of these structures will be found in the Trans. Eoy. Geol. Soc. 

 Cornwall, vol. sii (1901), pt. 6. 

 - Excluding the Carne quartzite. 

 3 J. B. Hill: Trans. Roy. Geol. Soc. Cornwall, vol. xH (1901), pt. 6. 



