TTTK MENDIPS : A OEOT.OCTOAT, RKVF.IUK. 



257 



Sonthorn Franco found access to the Woaldon Lake con- 

 verting it into a Vectian (lulf. The waters of the Speeton 

 Bay were also creeping np over tlie land, and beating on the 

 northern shore of a barrier extending from Belgium through 

 London and south-central England. This barrier separated 

 the northern waters of the Speeton Bay from the southern 

 waters of the Vectian Gulf, and as submergence continued 

 this barrier grow narrower and narrower uTitil the two wore 

 united by straits between Berkshire and Cambrido-oshire. 

 Tho straits widened and dooponod as England underwent 

 lior last great jioriod of subHidonce bonoath the waters of the 

 CJhalk Ocean, which teemed with the myriad life of minute 

 marine animalcules, the tiny shells of which sinking to the 

 bottom gave rise to a greyish calcareous ooze, which, now 

 that it is uplifted to form our downs and southern shore 

 cliffs, wo term chalk. Dartmoor, parts of Wales, and the 

 Cumbrian Lake Mountains, perhaps alone of all England 

 appeared as islands in the midst of the bine waters of the 

 warm clear sea. The Mendipa wore once more, and for the 

 last time, completely submerged.* 



Wiien they again rose from the waters they were ovor- 

 mantlod by a deposit of pure white chalk. But ovon as 

 they emerged from the ocean the waves were busy rapidly 

 removing the soft calcareous ooze, and when thoy had passed 

 through this ordeal and were lifted up once more into the 

 atmosphere, they were forthwith subjected to the action of 

 rain, tho weather and a thousand streamlets. Thus were 

 all tho more recent deposits stript from the Mendip axis 

 and tho old scenic features, so long buried, wore again dis- 

 closed, and received under the chisel of denudation their 

 linal sculpturing. Around them, mantling their flanks 



Near Frome tho Wonldon and Lowor Cretaceous are alment. The 

 Upper (rreonsand lies directly on an eroded surface of Oxford Clay. 



