RIVER 3IEDINA. 



141 



a transverse valley of the chalk range on the south, 

 and winding round the east end of the town, be- 

 comes navigable for vessels of considerable bur- 

 then, to its entrance into 

 £ 3 the sea at Cowes. The val- 



g ley of the Medina, like the 



river valleys of the North and 

 South Downs,* is a transverse 

 £ ■§ dislocation, or rent, across the 

 5 range of chalk hills, produced 

 » ° by the tension of the strata 



§ 3 I. during their elevation from 



S | s fo < 



g a, o the horizontal to their present 



8 c 7 nearly vertical position. 



a ^> I The transverse course of 



§ ! h the Medina through the mid- 



"f die of the central ridge of 



> ts chalk, is noticed by Mr. 



• Hopkins, in his memoir 



ft. — X 



z " On the Geological Struc- 



ture of the Wealden District, 

 T ««</ o/* £/^ Bas Boulonnais,"-f 



«^ with the accompanying dia- 



gram, %w. 10, which re- 

 presents an east and west section of the valley 



* Geology of the South-East of England, p. 350. 

 t Geol. Transactions, vol. vii. p. 24. 



h2 



m 



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