TRANSACTIONS OF THE SECTIONS. 67 



conjectured some years ago, from tlieir unconformability with the slates of Capo 

 Town, now shown to be probably Devonian, that they might be of Triassic age, or 

 possibly outliers of the Lacustrine formation. By these discoveries an area ex- 

 ceeding that of the British Isles requires transferring to ditierent formations. But 

 this was considered of minor importance in comparison with the relations of the 

 rocks which led Mr. Bain into error. The author had pointed out this relation some 

 years ago, and predicted that the primary clay-slate (Silurian and Carboniferous 

 beds of Bain) woidd probably prove to belong to one gTeat Palaeozoic formation. 

 The relation alluded to was" the conversion of beds of widely different ages, but 

 contiguous, into a quartzose sandstone or quartzite, causing beds of Silurian rock to 

 lie conformably on inclined quartzite, which was continuous with horizontal rock 

 of like character resting unconformably on Silurian rock. The quartzite mountain- 

 ranges extend from Table Mountain eastward to near the nioutli of the Great 

 Fish River ; but, while the sandstones of which they are composed are imcon- 

 formable in the west, they are interstratified with the Palaeozoic schists in the 

 east, — still, however, crossing their strike at an angle of 30° or more, and by spurs 

 in other directions, so modifying the sections that two lines across the strike, dis- 

 tant only a few miles, often cross wholly diiferent rock, one section being quartzite 

 with but a few interlaminated schists, the other all schist. This was explained in 

 tlie same manner as above, ^-iz. by the silicitication of the beds of schists, the 

 mountain-chains originating eitlier in the silicifpng action taking certain lines, or 

 in denudation into their present forms. Reasons were given for believing this 

 silicification to be a surface-change due to aqueous action. There are no igneous 

 rocks in the parts most ailected by this change, and the cuttings made by rivers and 

 by artificial means through the quartzite often expose the slate at the bottom. 



On some New Forms of Olenokl TrUoUtcs from the Loivest Fossiliferous BocJcs 

 of Wales. By J. W. Salter, A.L.S., F.G.S. 



The grey rocks and black shales at the base of the Lower Lingula-flags, in which 

 ]Mr. Salter discovered, two years ago, the great Puradoxides Davidis, are being fully 

 explored (-ndth the aid of a grant from the British Association) by Mr. Henry 

 Hicks. His energetic work has akeady brought to light more than thirty species 

 of fossils, most of them Trilobites. Some of these are quasi-embryonic forms, such 

 as Microdiscus, which, like Agnostus, is a blind Trilobite without facial sutures ; 

 but it has four body-rings, instead of two. There are also species of Conocoryphe 

 and Agnostus, both of them well-kno-v\Ti genera, and others allied to Arionellus of 

 Barrande ; all of them have a ' primordial ' aspect. Among the new discoveries is a 

 genus ns.-m&&. Atiopolenus, a remarkable form, which at first seemed to have the head 

 devoid of eyes and of any facial suture. Later observations, however, have dis- 

 cerned the cheeks, eyes, and head-spines in a most abnormal position — placed far 

 forward on the head, and so easily separable as to justify the previous belief in thek 

 entire absence. In order to find a parallel for this bizarre form, the author was 

 obliged to describe a new Olenus, or rather Spharophihabnus, found bj' Mr. Turner, 

 of Pauntley, in the Black Shales of Malvern. In this fossil the characters so much 

 exaggerated in Anopolemis are less strongly pronoimced ; and the new genus is thus 

 connected with the older and better known forms of the Olenidce, the most ancient 

 TrDobite family, — if we except Agnostus and its allies which were probably coeval 

 with them. It is worthy of remark that in this earliest family (Olenidte) the 

 largest size attained by the group of Trilobites is reached, the great Paradoxides 

 Harlani being nearly 22 inches long. 



In reply to a question put by Mr. Pengelly, Mr. Salter stated that the exceptional 

 blind species found in the latest formations known to contain Trilobites are degraded 

 forms of the highest genera, namely, Phacojis and PhiUipsia, and that there is good 

 evidence of a progression in the development of the gToup from its commencement 

 in the Cambrian to its extinction in the Coal period. 



On the Old Pre- Cambrian (Laurentian) Island of St. David's, Pembrol-esliire. 

 Bg J. W. Salter, A.L.S.,' F.G.S. 

 Having been occupied for a fortnight this summer in searching (with Mr. H, 



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