xlii PROCEEDINGS OF THE GEOLOGICAL SOCIETY. 



beds. Phsenomena like those recorded by Professor Buckman should 

 therefore serve as pilot facts, and guide us to fresh discoveries. 



The upper Mesozoic rocks of Britain have been of late left undis- 

 turbed, with the exception of that very moveable and problematical 

 deposit, the sands and gravels of Farringdon, which Mr. Sharpe would 

 elevate to a considerably higher position in the cretaceous series than 

 has hitherto been assigned them. The time is probably fast approach- 

 ing when the conflicting views upon this disputed question will be 

 tested by fresh data. For the present I abstain from taking up this 

 critical subject. 



Our Tertiaries, on the other hand, have been treated with much 

 favour, and form the subject of several memoirs, at the head of which 

 stands Mr. Prestwich's account of the "Woolwich and Reading series. 

 This paper completes the series of memoirs by that eminent geologist 

 descriptive of the Lower and Middle Eocene strata of England. 

 These remarkable essays embody the results of many years' careful 

 observation, and are unexcelled for completeness, minuteness of 

 detail, and excellence of generalization. They have a further merit, 

 and a very great one, to wit, that whilst in themselves essentially 

 local and topographical, the examination of the British strata which 

 they profess to describe has been conducted pcwi jjassu with per- 

 sonal comparisons and examinations of corresponding formations on 

 the continent. This method of treatment, broad and catholic m its 

 spirit, has made the essays of Mr. Prestwich as useful to foreign as 

 to British geologists, and secured for their author a European renown. 

 The special subject of the last of these papers is the series of strata 

 constituting what is usually known as the Plastic Clay formation, the 

 mutual relations of whose several local beds had never been clearly de- 

 termined, and the relativepositionof thebedsof theReculversandHerne 

 Bay to those of Woolwich and Reading were quite unsettled. This 

 condition of things can be said to exist no longer, and we have now, 

 instead of confusion and uncertainty, a clear statement and correlation 

 of the local phsenomena at numerous points, with a thorough revision 

 of the lists of organic remains, and most interesting generalizations 

 respecting the geographical and dynamical changes that affected the 

 area during the epoch under review. Since the memoir is printed at 

 length in the first number of our Journal for 18.54, I need attempt 

 no detailed analysis here, or enter upon the many important questions 

 and suggestions that are in it discussed. 



It has been my own lot to investigate the fluvio -marine series that 

 terminate the Eocenes in the Hampshire basin, and to lay before you 

 a preliminary statement of the results at which I have arrived. The 

 demonstration that a considerable and hitherto unplaced portion of 

 these beds in the Isle of Wight represents the Limburg series of 

 Belgium and the Upper Eocene or Lower Miocene of France, as well 

 as other continental formations, of which we were supposed to have 

 no equivalent in England, will, I trust, prove acceptable to all who 

 take interest in Tertiary geology. Since I communicated my paper to 

 the Society, I have revisited and carefully re-examined the iiuvio- 

 marines of Hempstead and those west of Yarmontli ; also the sections 



