252 GEOLOGY OF THE ISLE OF WIGHT. 



gular terrace composed of fallen masses of chalk, 

 marl, and firestone, which in the lapse of cen- 

 turies have accumulated in a talus on the southern 

 escarpment of the Downs. Although subsidences 

 are occasionally taking place, and within the last 

 hundred years, from eighty to ninety acres of the 

 upper cliff sunk down at one time, the greater part 

 of this singularly picturesque and lovely region 

 has undergone no material change since the Con- 

 quest. This is evident from the ancient churches of 

 St. Lawrence, and St. Boniface, which are referred 

 by antiquaries to the eleventh or twelfth cen- 

 tury.* In travelling from Blackgang to Ventnor, 

 the firestone cliffs are the most important geolo- 

 gical feature. Here and there on the road side 

 are seen accumulations of debris, and projecting 

 crags of chert and sandstone, which from their 

 superior hardness have for years resisted the dis- 

 integrating effect of the elements. From the in- 

 termixture of calcareous and argillaceous earth 

 resulting from the decomposition of the strata, a 

 soil has been produced which supports a luxuriant 

 vegetation. Even the refractory siliceous rocks are 

 more or less clothed with foliage, for the ivy has 

 insinuated itself into every cranny, and hangs in 

 festoons of verdant tapestry over the cherty peaks. 



* Sir Henry Englefield ; Isle of Wight. 



