Notices of Memoirs — Prof. Oroom — Hollyhush Conglomerate. 471 

 V. — The Pebbles of the Hollybush Conglomerate, and theie 



BEARING ON LoWER AND CaMBRIAN PaLJEOGEOQRAPHT.* By 



Professor Theodore Groom, M.A., D.Sc. 



rpHE Malvern Hills are commonly supposed to have formed part 

 X of an old coast during the deposition of the Lower Palasozoic 

 beds. A preliminary examination of the materials of the Hollybush 

 Conglomerate by the author does not support this view. 



The most abundant pebbles consist of quartz ; these vary from 

 a coarse mosaic of crystals to a fine quartz-schist. Most of the 

 varieties are probably of metamorphio origin ; some appear to be 

 merely vein-quartz, and some represent the quartzose portions of 

 granites and other rocks. Red granites and granophyres, often 

 crushed, are tolerably abundant; these often contain microcliue. 

 Mica-schist and chlorite-schist occur rarely. Very abundant are 

 dilferent varieties of felsite. These appear to be mostly micro- or 

 cryptocrystalline, and often micrographic, rhyolites, compact or 

 porphyritic ; sometimes banded, and occasionally spherulitic. Some 

 of the varieties may represent crushed intrusive felsites. Far rarer 

 than the rhyolites are microlithic andesites, or andesitio basalts. 

 Other pebbles, and the grains of the groundmass, consist of materials 

 derivable from the rocks mentioned above. 



The resemblance of these materials to the rocks of the Malvern 

 range is sufficiently close to 'prove the Pre-Cambrian age of the 

 latter. But striking differences in microscopic structure and in the 

 proportionate numbers of corresponding rocks in the two series, and 

 the absence of any relation between the local nature of the con- 

 glomerate and that of the Archjoan mass nearest to it, can hardly be 

 explained except on the assumption that the range itself did not 

 furnish the materials. 



The etratigraphical relations of the conglomerate and Archseau 

 mass, moreover, appear to indicate that the Malvern Hills — the 

 southern portion at least — in Cambrian times formed part of an 

 area of deposition, and not of denudation. 



The author maintains, then, that the Malvern Hills did not form 

 a coastline in Cambrian times, a conclusion which is in agreement 

 with his former contention that they arose at a much later date. 



VI. — Suggestions in regard to the Registration of Type 

 Fossils.^ By the Rev. J. F. Blake, M.A., F.G.S. 



WHEREAS : 

 1. There is now in existence, and has been for some time, 

 a Committee of the British Association " to consider the best 

 methods for the registration of all type-specimens of fossils in the 

 British Isles." 



2. There is as yet in course of production no general register of 

 such specimens. 



3. The original types are in many, perhaps the majority of, cases 

 either lost, inaccessible, or inadequately preserved or described. 



^ Eead before the British Association, Section C (Geology), Bradford, Sept., 1900. 



