SEDGWICK ON THE MAY HILL SANDSTONE. 223 



a good Wenlock group of fossils, it seems, in sound logic, to confirm 

 rather than invalidate my previous conclusion, viz. that the May Hill 

 sandstones are a part of the Wenlock group, and not a part of the 

 true Caradoc group. That these sandstones of May Hill are a part 

 of the true Wenlock group, appears from their place in the section, 

 their passage beds, and their fossils. And spite of the continuance 

 of an older mineral type, vphich apparently offers good conditions for 

 the uninterrupted life of the older (or Cambrian) species, such species 

 are not continued, so as to pass upward into the May Hill sandstones. 



The sections on the West side of the Malverns are so weW known 

 to all who can take any interest in this paper, that I hardly need 

 copy or discuss any one of them ; but I think it expedient to copy 

 the vertical, ideal, section, in which Professor Phillips represents the 

 whole series of the palaeozoic groups which are brought out on the 

 western slopes of the Malvern Hills (Fig. 4) . 



The above ideal vertical section applies specially to the sections 

 here under notice, and is, I believe, perfectly accurate. Nos. 1 and 2, 

 the Hollybush sandstone and the Black shales, here skirt the bosses 

 of syenite, in the manner described in detail by Professor Phil- 

 lips, and form the base of the series hitherto described collectively 

 under the name of Caradoc sandstone. Adopting this nomenclature, 

 so far as I believe it tenable, I should provisionally call No. 1 Caradoc 

 sandstone, and No. 2 Caradoc shale ; which, I believe, agrees with 

 Professor Phillips's view*. This sandstone is unfortunately very 

 sterile of fossils ; but along the western skirts of the Malvern syenites, 

 there are (as has been described in the Memoirs of Murchison and 

 Phillips) several spots in which groups of rocks are found containing 

 fossils. And should any of the beds, in this skirting position, contain 

 a group of true Caradoc fossils, we should, of course, place them at 

 the base of the Malvern series ; but, north of Hollybush, no such 

 beds fell under our notice. 



The Black Shales (No. 2) are so interlaced with the neighbouring 

 sandstones as not, I think, to be separable from them. This is also 

 the published opinion of Professor Phillips. There is nothing in the 

 mineral structure of the shales to indicate a rock of great antiquity ; 

 and if this remark were regarded as of little moment, I should add, 

 that there is nothing in the position of the shales to indicate the fact 

 that they had been anomalously protruded among the neighbouring 

 sandstones. This opinion of an anomalous protrusion of a very an- 

 cient rock (viz. the Tremadoc slate^ which is low in the great Cam- 

 brian series) was not vindicated by Prof. Phillips ; but has no doubt 

 been suggested by the fact (first published in his Memoir), that im- 

 perfect portions of two small new species of Olenus, and the frag- 

 ment of another doubtful species, had been found among these Black 

 shales. Assuming, without reserve, the truth of these determina- 

 tions, what do they appear to prove 1 Only that the genus Olenus, 

 which began during the very early deposits of North Wales, still ex- 

 isted, though very rarely, during the period of those rocks which 

 form the newest members of the great Cambrian series. 



Much time was lost by Prof. M'Coy and myself in seeking for the 

 * Memoir, p. 53. 



