53 



periods, and in each district the direction of the sag produced by 

 them seems to have been the same at each period. Thus, in South 

 Wales, and the South of England, from Devon to Kent, the trend 

 is east and west ; in the Pennines, north and south ; in the 

 Mendips, east and west ; at Charnwood Forest, north-west and 

 south-east. 



The origin of the Hampshire basin must therefore be referred 

 to crust movements, caused by a diminution of pressure, produced 

 by the great lava outbursts which closed the Tertiary period. 



Continuing the subject on March ist, the structure 

 f t e of the Hampshire basin was considered. The 



?_ e oldest rocks were found in Wales and the South- 



Ba^n & west of England, whilst on travelling eastward 



newer and newer rocks were passed over, the most 

 recent of all being in the Isle of Wight. Only one more recent 

 formation occurred in Norfolk. These older rocks formed the 

 floor of the basin, which was like a spoon filled with chalk, gravel, 

 sand, and mud. The floor of the basin was sagged downwards and 

 its surface eroded. If one stripped off the chalk which lined the 

 basin, underneath we should find Weal den beds ; if these were 

 removed Jurassic would appear, and so on, until after removing 

 many different layers of strata we came to the old Archaean rocks, 

 which formed the foundation of the earth's crust. The Hampshire 

 basin was lined by chalk, which appeared in its northern and 

 southern boundaries as the South Downs and the ridge of the Isle 

 of Wight and the Purbeck Hills. The Tertiary beds which filled 

 the basin were very soft, and consisted largely of sand, gravel, and 

 mud. Hence the basin has been much cut up and broken by 

 streams, far more so than the Thames basin. Various chines, 

 inlets ot seas, estuaries of rivers, etc., mark the Hampshire coast, 

 the existing scenery being what has escaped the denuding influences 

 of water since the contents of the basin were deposited. The 

 many layers of strata deposited in the basin since the chalk was 

 raised up from the sea are the results of several raisings and 

 depressions of the surface above and below sea level. Some beds 

 have been partly washed away, and others deposited in their place. 

 Each time the floor sank it was covered with fresh material by sea 

 or rivers and streams. Each time it rose it was eroded and partly 

 dissected out by atmospheric agents — chiefly water. At present 

 we live in a "continental" phase, when atmospheric denudation is 

 taking place, the surface being raised above sea level. 



The Ham shir ^his subject was dealt with on Wednesday, March 

 Basin • ' I 5^ 1 ' The preceding lecture was not delivered by 

 its Contents Sp icer owing to illness, and Dr. Ord had been 



invited by the University Extension authorities to 

 deliver the lecture on " The Contents of the Hampshire Basin," in 

 Mr. Spicer's place. In so doing, Dr. Ord made use — by kind 

 permission of the Council — of a series of slides prepared for two 



