Reports and Proceedings — Geological Society of London. 233 



scale, sliding along the base band, itself traversed by long oblique 

 faults, represented Glasven in miniature. In other experiments the 

 mass of faulted bands tended to curve forwards and downwards on 

 and beyond the faulted basement, thus giving "an elementary model 

 of parts of Ben More, Brebag, Ben Thuarain, and other mountains " 

 (p. 74). The probable behaviour of the earth's internal mass under 

 the regions of such faults and thrusts is considered, with reference 

 to another experiment (fig. 11). 



The schists, eruptive rocks, and Old Eed Sandstone of the rest of 

 Sutherland, also the remaining evidences of the Great Ice Age, and 

 the relics of Jurassic strata and coal at Brora, are succinctly treated. 

 The interesting but not very productive gold-field of Sutherland has 

 a short chapter (pp. 95-108). 



The excellent illustrations of the local " bens " and glens, and the 

 two good maps, add much value to the book. One map gives the 

 relative height of the land ; and the other deals with the geological 



T 1 1 



structure. It has a careful diagrammatic section of the strata from 

 Cape Wrath to the border of Caithness ; and a useful diagram 

 showing the successive stages of rocks and strata, with their uncon- 

 formities, displacements, and intrusions. 



The information given in this little book on Sutherlandshire, 

 brought together by a well-informed, enthusiastic, and trustworthy 

 geologist, and not easily accessible otherwise, will be very useful to 

 geologists at home or in the field ; and ought to be in the hands 

 of tourists, whether artist, sportsman, yachtsman, or idler. 



REPORTS -A-ZDnTID ZE'ROCIEIEIDX.IENrG-S- 



Geological Society of London. 



I.— February 26th, lS9b\— Dr. Henry Hicks, F.R.S., President, 

 in the Chair. The following communications were read : — 



1. " On the Structure of the Plesiosaurian Skull." By Charles W. 

 Andrews, Esq., B.Sc, F.G.S. 



Owing to the imperfection of the specimens described, various 

 previous accounts of the Plesiosauriau skull are incomplete, and 

 differ from one another in important particulars. There is in the 

 National Collection a fine skull of Plesiosaurus macrocephal us which 

 has lately been cleared from the matrix, with a description of 

 which the present communication is mainly occupied, though other 

 specimens, which are of assistance in clearing up some difficulties, 

 are also noticed. The author particularly considers the structure of 

 the palate, and only such points in the structure of the rest of the 

 skull as add to or are at variance with previous descriptions are 

 considered. 



The author's observations indicate that a general similarity of 

 palatal structure among reptiles does not necessarily imply any 

 close relationship ; but the very great resemblances existing between 

 the Plesiosaurian and Bhynchocephalian palates, reinforced by 



