of f 



(Being the Mansel-Pleydell Prize Essay, 1909-10.) 



By Dr. W. THEOPHILUS ORD. 



geology of the district of Dorset traversed 

 by the Purbeck Hills has been exhaustively 

 treated by many able geologists ; but it 

 contains three problems of great interest which 

 have not yet been satisfactorily solved. These 

 are, in brief, (1) The mode of formation of the 

 great Purbeck Thrust-Fault in the Chalk ; 

 (2) the origin of the Corfe Monticle on which 

 Corfe Castle stands ; and (3) the details of the vast processes of 

 denudation by which the enormous mass of strata that 

 within recent geological times, possibly since Oligocene days, 

 has been removed from the southern half of the Isle of Purbeck, 

 that is, south of the Purbeck Hills. The present paper 

 comprises (I.) a general sketch of the geology of this district, 

 and (II.) an account of the author's studies and researches 

 which it is hoped may advance our knowledge of these three 

 problems a step or two further. 



