XXXVl PROCEEDINGS OF THE GEOLOGICAL SOCIETY. 



however minutely subdivided, could scarcely lead to the formation 

 of agates ; and that it is more probable that the passage of highly 

 heated steam through the rocks, under the influence of some kind 

 of igneous action, has led to the solution of the silica, and its subse- 

 quent deposition in the cavities of rocks. 



In the second paper, the discovery of the bones of an Iguanodon in 

 the ironsand of the Wealden of the Isle of Wight and in the Isle of 

 Purbeck is announced ; its range being thus extended from Tilgate 

 Forest, where it was first discovered by Dr. Mantell. These bones 

 were accompanied by others of the Megalosaurus ; and at Sandown 

 Bay specimens of a Zamia, Zamia crassa of Lindley, were also found. 



Such papers as these are most curious, as they show the careful 

 but sure steps with which our early masters in this science tried their 

 way, when walking in a hitherto almost unknown track and putting 

 together, one by one, those links which were to be afterwards more 

 completely combined into one whole. 



February 7, 1825. — Dr. Buckland read a very interesting paper on 

 the *' Formation of the Valley of Kingsclere," and other valleys by 

 the elevation of the strata that enclose them, and not by denudation. 

 In this paper he explains the peculiar characteristics of such valleys 

 in being surrounded by bold escarpments, the strata of which dip 

 away from each other outwards. He then referred to the great 

 valley of the Weald, and, applying his reasoning to it, he says that no 

 force of water alone could have produced such effects as are here ob- 

 served, though he was disposed to admit that such force might have 

 been sufficient to remove the rubbish resulting from the previous 

 disturbance, fracture, and elevation of the strata. 



Following up the argument, he demonstrates that the Hampshire 

 and London Tertiary Basins were probably separated from each other 

 by the elevation of the subjacent chalk subsequent to the deposition 

 of the strata of which they are formed, and points out as a confirm- 

 atory fact, that on the summits of some of the highest chalk hills 

 between them are isolated masses of strata, of which the identity of 

 character with that of the plastic-clay-formation in the basins of 

 London and the New Forest affords abundant ground for concluding 

 that these two basins were originally united together in one continued 

 deposit across the intervening chalk of Salisbury Plain in Wilts, and 

 the plains of Andover and Basingstoke in Hants ; their separation 

 into the two distinct basins of London- and Hampshire having re- 

 sulted partly from local elevations and depressions, by subterranean 

 violence, since the deposition of the plastic clay ; and partly from 

 the still more recent removal of much of their substance by diluvial 

 denudation. 



A similar conclusion, bold as it must have then been considered, 

 Dr. Buckland also drew from the position of insulated portions of 

 tertiary strata, at elevations of 10,000 feet above the sea level in the 

 Alps, as compared with that of the tertiary strata of the valleys of 

 Italy, France, and Germany ; so that here too he was the precursor 

 of our most able living geologists. 



April 18, 1828. — In this paper Dr. Buckland details the results of 



