366 Geological Society. 



pointing to Higli Teesdale as the seat of its origin, traverses the 

 southern coal measures of Durham, and seeming to plunge beneath 

 the magnesian limestone, re-appears and continues its course even 

 through the lias and inferior oolite of the Yorkshire Moorlands. 



From my own observation in Teesdale, 1 am of opinion that Pro- 

 fessor Sedgwick has faithfully described the facts ; and has irresistibly 

 proved the basalt of that district to have been injected laterally; be- 

 cause the overlying depositary beds are quite as muchaltered in struc- 

 ture, as those immediately below the basalt. 



In this discussion, however, we should recollect, that IN'Ir. Hutton 

 has drawn his inferences chiefly from the Northumbrian district, and 

 Professor Sedgwick solely from High Teesdale; whilst the truth may 

 be, that no one portion of this vast range of country can be selected 

 as a type, whereon a theory explanatory of all the phaenomena 

 can be constructed ; and, as there are independent proofs of seve- 

 ral distinct periods of volcanic action in those northern coun- 

 ties, we may feel warranted in endeavouring to explain the phaeno- 

 mena of the whin sill by reference to volcanic operations of compa- 

 ratively modern date. In central France, for example, not only do 

 we see that basalt, in the form of dykes^ has cut through strata previ- 

 ously consolidated ; but w^e have in the very same district, evidence 

 of a continuous series of igneous operations, exhibited in nearly every 

 possible form, from the outburst of sub-lacustrine volcanic ejections, up 

 to sub-aerial craters, which have vomited forth scoriae and streams of 

 lava : and hence we may, without a strained hypothesis, be disposed 

 to think, that in the elevated region of Western Northumberland, 

 currents of submarine volcanic matter found issue at intervals, which 

 were continued even beyond the period when the oolitic deposits 

 were accumulated. 



Mr. Phillips, so well known to vou all as the author of that excel- 

 lent work 'The Geology of Yorkshire,' the second volume of which I 

 rejoice to say is now in preparation, has given us an interesting prelude 

 to a more detailed memoir upon the various modes by which the 

 atmosphere wastes the surfaces of rocks and buildings ; a subject 

 which he intends to follow up with copious details, and which must 

 be of essential use in serving to explain many changes continually 

 operating upon the crust of the globe. 



A series of observations, made by Mr. William Bland, on the wells 

 in the strata above and below the chalk, both in the Weald of Kent 

 and on the adjacent hills, acquaints us with the curious fact, that the 

 water is always highest about the summer solstice, and lowest about 

 Christmas; and that throughout the district examined, the same law 

 prevails in the waters derived from all the strata, whether consisting 

 of chalk, sand, or clay*. 



At the conclusion of our last session a letter from Mr. Trimmer 

 to Dr. Buckland, gave us an account of ceftain diluvial deposits of 

 Caernarvonshire, between Snowdon and the Menai Straits, and of the 

 discovery of marine shells in diluvial sand and gravel on the summit 



* Mr. Bland's observations will be found in our Number for February. — 

 Edit. 



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