1854.] DAWSON — SUBMERGED FOREST. 119 



The position of the gravels of the coast of France shows how very 

 great has been the change of level around the English Channel area* 

 since the period of their dispersion. 



The formation of valleys, such as those of the French chalk-area, 

 may seem to some to require an agency more powerful than that now 

 suggested ; but, taking as our guide the quantity of lime taken up by 

 every gallon of rain-water which flows from our own chalk-district, 

 the question becomes one of time, in the course of which every line' 

 of inequality along which water may flow must ultimately be deepened 

 and widened out. This is not the place for details of such a calcula- 

 tion ; which, with other effects of subaerial agency, I propose to 

 submit collectively. If the cause be the true one, we have the data 

 for the determining the lapse of time from the elevation of the Drift- 

 beds down to the times in which we live ; and, however vast that 

 period may seem, which is but the newest date in our geological 

 reckoning, we must not on that account merely reject the result. 



The extent of the hydrographical area of the southern counties of 

 England and of the opposite side of the Channel during the period 

 of the distribution of the Drift-gravel can now be determined with 

 tolerable accuracy, by combining the results of several observers 

 (more particularly those of Mr. Prestwich and Mr. Morris) who 

 have noticed and described them. Over the whole area I have never 

 seen, or even heard of, the presence of a single form which would in- 

 dicate marine origin. In spite of the great extent of the area, I 

 believe the body of water to have been fresh ; and, as a whole, it 

 may be geologically the equivalent of some of the northern gravel- 

 drifts, which were undoubtedly marine. 



The climatal conditions are, I think, indicated by the manner in 

 which large blocks of siliceous sandstone have been lifted and let fall 

 amidst accumulations indicating no great moving power. Such ap- 

 pearances are well seen in the drift-area to the north of the chalk- 

 range of Surrey, particularly about Ash. The distance from which 

 these blocks have been moved cannot have been very great ; and the 

 only condition which seems to meet the requirements is one — where 

 coast-ice was periodically formed and dispersed, carrying with it such 

 materials as might be included in or attached to it. 



January 3, 1855. 



Dr. A. Halley was elected a Fellow. 



The following communications were read : — 



\. On a Modern Submerged Forest at Fort Lawrence, 

 Nova Scotia. By J. W. Dawson, Esq., F.G.S. 



The extraordinary tides of the Bay of Fundy, and its wide marshes 

 and mud-flats, are well known to geologists as affording some of the 

 best modern instances of rapid tidal deposition, and of the preserva- 



* See Quart. Journ. Geol. Soc. vol. vi. p. 69, and vol, vii. p. 118. 



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