90 Reports and Proceedings. 



resemblance to glacial gravels ; but as they here and there contain 

 recent shells, and taking into consideration their uniformity of level, 

 the author concludes that they indicate an ancient course of the 

 Eiver Cam. 



The other conclusions arrived at, after mature consideration of all 

 the evidence hitherto obtained, are — that a gradual passage will be 

 found to exist from the base of the Crag up to and through the drift 

 deposits to those of recent date; that in East Anglia we have evi- 

 dence of but one, and that a gradual, period of glacial submergence, 

 succeeded by a corresponding movement of re-elevation ; and that 

 there are no " middle-glacial " deposits whatever within the area of 

 the Cambridge valley. 



2. "Denuding Agencies and Geological Deposition under the 

 Flow of Ice and Water, with the Laws which regulate these actions, 

 and the special bearing on river-action, of observations on the 

 Mississippi and other great rivers, and their present and past Meteoro- 

 logical conditions, and similar remarks on Marine Deposits, illustrated 

 by the Irish Sea and the Chesil Beach." By A. Tylor, Esq., E.G-.S.^ 



The author's remarks were illustrated by diagrams of carefully 

 measured sections, of instances of deposition and denudation. From 

 these he inferred that the present contours of hills were formed 

 in a previous Pluvial Period, when rivers and springs, winds, 

 currents, and tides, were of greater force than at the present time. 

 He thought the immense size, height and position of Quaternary 

 Gravels, when compared with recent deposits, afforded evidence of a 

 rainy more than an icy period. 



It was remarkable that the great Playfair, the original advocate 

 of Land Ice as a geological agent, was not acknowledged as the 

 author of this great discovery by either Agassiz, Lyell, J. Croll or 

 James Geikie. His merit was, however, fully admitted by d'Archiac 

 and the late Professor James Forbes, of Edinburgh. 



One of Playf air's original and accurate remarks in 1813 was that, 

 "after glaciers, torrents were the most powerful agents of denudation." 



Mr. Tylor illustrated his paper by accurate drawings of Black 

 Gang Chine ; part of the Undercliff, Isle of Wight ; Oliver's Mount, 

 near Scarborough ; Fairlight and Ecclesbourne Glen, near Hastings ; 

 the Ehondda Yalley, S. Wales, etc., to show that the contours in such 

 strata could only have been formed in a wet climate. These do 

 not now change perceptibly, except in wet districts, as S. Wales. 

 The writer then compared the 16 inches of rain and snow in winter, 

 with the 64: inches in summer in Westmoreland, and also remarked 

 that the 30 inches rain and snow in winter in Switzerland only 

 rising to 42 inches in summer, show the probability that rainfall 

 was much greater everywhere in the whole year than snow — snow 

 being probably limited to 9 months of winter alone, even in the 

 Glacial Period. Both rain and snow diminished in quantity at heights 

 of more than 2000 feet above the level of the sea in Westmoreland, 

 and above 6000 feet in Switzerland. Mr. Tylor concluded that as 



' This abstract of Mr. Tylor's paper lias been furnished by the author, and is in- 

 serted by his special desire as more fully expressing his views. — Edit. Geol. Mag. 



