Outlines of Geology. 187 



such a' remarkable collection of sea-shells, shark's teeth, bones of 

 the elephant, hippopotamus, ox and deer, together with fresh- 

 water shells, as to impress us with the idea of the destruction or 

 relics of a vast menafjerie^ in which animals of all denominations, 

 and from all quarters of the globe, had been associated. 



The clay formation of London and its vicinity, is thrown into 

 many picturesque irregularities, which are hidden by the build* 

 ings of the metropolis, but which are seen in Shooters Hill on 

 the east, in the hills of Hampstead and Mighgate on the west, and 

 which contribute to the unrivalled beauty, in this line of pros- 

 pect, of Richmond Hill in the west. 



In the Isle of Wight, at its west extremity, there is a section of 

 the deposits superior to the chalk, attended however by some pe- 

 culiarities to which I shall advert more in detail. They are espe- 

 cially remarkable for furnishing alternations of marine and fresh- 

 water shells, from which it has been conjectured that the spot has 

 been subjected to alternating inundations of the sea, and that in 

 some part of the intervening period, it has formed the bottom of 

 a freshwater lake. 



If we travel from London to Paris, we find, in the vicinity of that 

 metropolis, facts equally irreconcilable with all commonly adopted 

 theory, and in most respects resembling those which the London 

 Ifatiny as it has been called, exhibits ; for, if we suppose a large 

 cup or concavity, scooped out of the chalk, imperfect in certain 

 parts upon the sea-coast, where sections of its contents are exhi- 

 bited, and filled up with sand, clay, organic relics, and alluvial 

 products, we shall form a tolerably accurate notion of the general 

 character of these districts. 



In the Paris basin then, the first substance that occurs, lying im- 

 mediately upon the chalk, is a layer of plastic clay fit for the manu*' 

 facture of pottery, and upon this is a coarse limestone, with beds of 

 sandstone and marie, enclosing marine petrifactions of various 

 kinds, and many shells which still retain their pearly lustre. 

 This stratum, however, is not quite continuous, for, in some places, 

 its space is occupied by a siliceous limestone without any shells. 

 We may, however, from the position and contents of this stratum. 



