40 



^^' STRATA IN THE NEIGHBOURHOOD OF LaNl>0\'. 



geology may derive considerable assistance, from an exami- 

 nation of fossils, made in connexion with that of the strata 

 Straulnthe to which they belon-. 



vicinity of The followincr is an attempt to investigate on this plan 



London. some of the upper strata in the viciuity of the metropolis 



v.'ith their contained fossils; and, although by no means 

 complete, it will, it is hoped, induce others, who possess su- 

 perior abilities and opportunities, not only to reexumine 

 more correctly these strataj, but to extend their researches to 

 the subjacent strata, 

 strala hlye '^^^^ whole of this island displays evident marks of its 



been consider Stratification having, since its completion, suffered consider- 

 ably disturbed, jjjjjg disturbance, from Some prodigious and mysterious 

 power. By this power all the known strata, to the greatest 

 depths that have been explored, have been more or less 

 broken and displaced ; iind in some parts have been so lifted, 

 that some of the lowest of these have been raised to the sur- 

 face ; while portions of others, to a very considerable depth 

 and extent, have been entirely carried away*. From these 

 circumstances great difficulties and confusion frequently 

 thoi' Lr — ^'^ iivht in examining the superior strata: the counties however 

 immediately surrounding the metropolis, us well as that on 

 which it stands Inning suffc^red least disturbance, are those 

 in which an iavestit^ation of these strata may be carried on 

 with the smallest chance of mistake. 

 Real nlluvial ||^,.^| alluvial fossils, washed out of lifted or original sw- 



fo'isil.-; rarely . . '^ 



«eeii ncarLori- perior strata by strong currents, and which in other parts 

 are very abundant, are rarely seen in the counties adjacent 

 to the metropolis. This remark is rendered necessary, since 

 and and gra- those w*idely extended beds of sand and gravel, with sandy 



vel iioi ajlu- clay, sometimes intermixed and sometiujes interposed, and 

 which have been generally hitherto considered as alluvial 

 beds, are here assumed to ^bc the last or newest strata of 

 this island, slowly deposited by a preexistent ocean; with 



* See several cysnys on this siibiect in the Pliilo^ophicil Magazine, by 

 Mr. Farey, and the Report 0:1 Derbyshire, vol I, j). 105. 



Also d Letter on the alterations, which have taken place in the struc- 

 ture of rocks, on the surface of the basaltic counfry in the counties of 

 Derry and Antrim, by William Richardson, D D. Plui. Traas. ISOS : or 

 Journul, vol. XXll, p, iGl, ^-55. 



the 



dor 



ft^ bed; of 

 and 

 .-el 11. 

 Mai. 



