[ 498 J 



XLVJ. Proceedings of Learned Societies, 

 GEOLOGICAL SOCIETY. 



[Continued from p. 420.] 



January 4th, 1899— W. Whitaker, B.A., F.E.S., President, 

 in the Chair. 



HPHE following communications were read : — 

 -*- 1. ' Geology of the Ashbourne and Buxton Branch of the 

 London and North-Western Bailway. — Ashbourne to Crake Low.' 

 By H. H. Arnold-Bemrose, Esq., M.A., F.G.S. 



The southern part of the new railway from Ashbourne, through 

 Tissington and Crake Low, to Buxton exhibits several sections 

 in Trias, Boulder Clay, Mountain Limestone, and Yoredale Beds. 

 Interstratified with the latter is a thick bed of volcanic ash, with 

 thinner intercalations of tuff. "Within a mile of Tissington ash is 

 exhibited four times in the cuttings, and according to the view of 

 the author it is the same bed repeated by basins and domes, one 

 of the latter of which is faulted. While the rocks succeeding 

 the ash in some places are limestones, cherts, and shales of Yoredale 

 type, in one section they resemble more closely the upper beds of the 

 Mountain Limestone. The limestones are often dolomitized. The 

 ash-bed is 144 feet thick where fully exposed : it is stratified, the 

 beds varying in texture, and the lapilli in them range from micro- 

 scopic dimensions to 1 inch in diameter. The lapilli are glassy or 

 palagonitic ; but felspar-microlites are rare, and the rock of which 

 they are made has no counterpart among the lavas of the county. 

 The ejected blocks in the ash vary from several inches up to 

 1 foot in diameter, and are similar to the blocks in the vent at 

 Kniveton. The small lapilli scattered through the limestones are 

 generally converted into calcite or dolomite with oxide of iron. 

 The paper is illustrated by microscopic slides, and horizontal and 

 vertical sections of the cuttings and quarries described ; also by 

 hand-specimens, photographs, and lantern-slides. 



2. ' The Oceanic Deposits of Trinidad.' By Prof. J. B. Harrison, 

 M.A., F.G.S., and A. J. Jukes-Browne, Esq., B.A., F.G.S. 



' The object of this communication is to present some observations 

 on the succession and geological relations of the beds which have long 

 been known in Trinidad as the Naparima Marls. This name 

 was given by Messrs. Wall & Sawkins in 1860, on account of their 

 occupying a large part of the Naparima district east and south-east 

 of San Fernando. The beds so named formed one of the five series 

 which were described by these authors under the head of the Newer 

 Parian Group.' In his historical introduction Mr. Jukes-Browne 

 deals with the writings of Mr. Guppy and Prof. Harrison, and shows 

 that three definite issues are thus raised: — (1) Are the NarivaBeds 

 above or below the Naparima Marls ? (2) Do the Globigerina-mdiTh 



