250 GEOLOGY OF THE ISLE OF WIGHT. 



the physical geography of the Island, and the 

 range and extent of the principal groups of strata. 

 We are now on the western extremity of the 

 southern range of chalk downs which, as previously 

 explained {ante, p. 177), is separated by a con- 

 siderable district of greensand from the central 

 chain of hills.* This system of chalk downs 

 varies in breadth from half a mile to three miles, 

 and extends six miles in a direction E.N.E. and 

 W.S.W. from St. Catherine's-hill to Dunnose, its 

 eastern termination, which is nearly 800 feet high. 

 The intermediate parts of the range maintain an 

 elevation of from 650 to 800 feet, with the excep- 

 tion of a deep valley on the east of St. Catherine's, 

 through which the road to Niton passes ; and 

 another at Steephill called the Shute or Shoot, 

 above Ventnor, traversed by the road to Appul- 

 durcombe and Newport. A marl bank on the side 

 of the Shute abounds in fossils.-f- 



The strata of these hills are nearly horizontal, 

 having only a slight inclination to the south-east. 

 From Ventnor to St. Boniface Down, above Bon- 

 church,^ a distance of three quarters of a mile, the 



Refer to tin' diagram. /'/. vu. and the map, /'/. XX. 

 t Mr. S,i\hy informs me that In.' lias obtained from this locality turrUitet 



U , nautili, belemnites, and many other marl fossils. 

 t High up on the slope of tin- hill bursts forth a spring called SI. Boniface's 

 I snds have attached much veneration. 



