132 Geological Society: — 



stone ; they were found during last season in the brown dolomitic 

 shales accompanying the Olenellus-sh&les in the ' Fucoid Beds,' and 

 they were formerly detected in the third subzone of the ' {ripe-rock ' 

 in Sutherland. Their appearance on these horizons leads us to 

 cherish the hope that portions of Olenellus may yet be met with in 

 certain shales in the quartzites and probably in the lowest group of 

 limestone. 



The evidence now adduced proves (1) that the ' Fucoid Beds' and 

 ' Serpulite Grit ' are of Lower Cambrian age, the underlying 

 quartzites forming the sandy base of the system ; (2) that the 

 Torridon Sandstone, which is everywhere separated from the over- 

 lying quartzites by a marked unconformability, is pre-Cambrian. 



The Olenellus which has been discovered is described as a new 

 species (0. Lapworthi) closely allied to 0. Thompson!, Hall, from 

 which it differs chiefly in the arrangement of the glabella-furrows 

 and in the presence of a rudimentary mesial spine at the posterior 

 margin of the carapace. Remains of other species referable to 

 Olenellus are described, but these are too fragmentary for exact 

 determination. All are characterized by a reticulate ornamentation 

 similar to that described by Walcott in 0. (Mesonacis) asaphoicles, 

 Emmons. The remains consist chiefly of portions of carapaces. 



February 24.— W. H. Hudleston, Esq., M.A., F.R.S., 



President, in the Chair. 



The following communications were read : — 



1. " The Raised Beaches, and ' Head,' or Rubble-Drift, of the 

 South of England : their Relation to the Valley-Drifts and to the 

 Glacial Period; and on a late Post-Glacial Submergence. — 

 Part II." By Joseph Prestwich, D.C.L., F.R.S., F.G.S. 



The ossiferous deposits of the Caves of Gower are shown to 

 be contemporaneous with the raised sand-dunes between the beaches 

 and the ' head," and reasons are given for supposing that the ele- 

 vation of land which preceded their formation need not necessarily 

 have been greater than 120 feet. The mammalian fauna of these 

 caves is the last fauna of the Glacial or post-Glacial period, and 

 the ' head ' or Rubble-drift marks the closing chapter of Glacial 

 times. 



Evidence is given for considering that the ' Rubble-drift ' has 

 a wide inland range, and that to it are to be referred the ' Head ' 

 of De la Beche, the Subaerial Detritus of Godwin -Austen, the 

 Angular flint drift of Murchison, and in part the ; trail ' of Fisher 

 and the ' warp' of Trimmer, as well as other deposits described by 

 the author. The accumulation is widespread over the South of 

 England, and occurs in the Thames Valley, on the Cotteswold 

 Hills, and on the flanks of the Malverns. The stream-tin detritus 

 of Cornwall and the ossiferous breccia filling fissures (which must 

 be distinguished from the ossiferous deposits of the true caves) are 



