Beriews—W. A. E. JJssher's Triassic Rocks. 227 



answered. The Glacial deposits and the Glacial strias are fully 

 described, as well as the Post-Glacial Peat and Forest-beds, aud 

 other Eecent deposits ; and the author concludes with some brief 

 remarks on the Origin of the Mersey. 



The labours of other geologists have received attention, i-eferences 

 being made more especially to the papers by Prof. Hull, Dr. Eicketts, 

 Mr. Mellard Pieade, Mr. C. E. De Ranee, and Mr. A. Strahan. No 

 reference, however, is made to Mr. Mellard Reade's paper on the 

 Physiography of the Lower Trias (Geol. Mag. 1889, p. 549) ; 

 possibly his views on this subject were considered too heterodox to 

 be mentioned. The author, moreover, has received special help in 

 some instances, Mr. R. Kidston having furnished a valuable list of 

 fossil plants from the Coal-measures of Ravenhead, near St. Helens ; 

 and Mr. J. G. Goodchild having contributed notes on some of the 

 rocks found in the Glacial Drifts. Combining as it does the results 

 of long-continued personal observation, Mr. Morton's book furnishes 

 an authoritative guide to the student, and will be of essential service 

 to all geologists who seek acquaintance with the geology of the 

 country around Liverpool. H. B. W. 



V. — The Triassic Rocks of West Somerset, and the Devonian 

 Rocks on their Borders. By W. A. E. Ussher. Proc. 

 Somerset Arch, and Nat. Hist. Soc. Vol. XXXV. for 1889. (1890.) 



IN this paper Mr. Ussher sums up the results of his observations 

 on the Devonian rocks of the Quantock and Brendon Hills, 

 and of the neighbourhood of Porlock and Minehead ; and he gives 

 his latest views on the Triassic rocks that border these old rocks 

 near Stogumber, Williton, and Porlock. The sandstones, breccias, 

 conglomerates and marls of the New Red Sandstone series, are all 

 grouped with the Trias ; but some changes have been made by Mr. 

 Ussher in his grouping of beds at particular localities. Thus he 

 now recognizes no divisions older than the Keuper, among the New 

 Red rocks west of Williton, and believes that the coarser beds of 

 the Keuper were accumulated higher and higher in the series in 

 that region, progressive subsidence having led to the continuation 

 of marginal deposition. 



With regard to the Devonian rocks, Mr. Ussher publishes a table 

 to show their general classification, and the correlation of the sub- 

 divisions in North and South Devon with those of Germany, France, 

 and Belgium. In West Soraei-set and North Devon there is a 

 much greater development of sandstones than in South Devon, for 

 the Cockington Sandstones of the Torquay district, at one time 

 regarded as Upper Devonian, are now placed (together with the 

 Lincombe and Warberry Grits) on the horizon of the Hangman 

 Grits of North Devon. It has been suggested that in North Devon 

 the Foreland Grits and Hangman Grits, which are of similar general 

 character, are the same. Mr. Ussher shows by diagram that this 

 may possibly be the case : but he gives various reasons, sufficient, 

 in his opinion, to negative the supposition that they are identical. 

 The Pickwell Down Sandstones, that were at one time grouped with. 



