288 GEOLOGY OF THE ISLE OF WIGHT. 



nisable specimens have been discovered in the 

 Isle of Wight. 



Fossil Ferns. — Entire layers of the sandstone, 

 grit, and shale, in Tilgate Forest, are so full of 

 carbonaceous matter as to acquire a dark mottled 

 colour, and this detritus is composed of minute 

 particles of the leaves and steins of ferns, that have 

 been ground to pieces by agitation in water loaded 

 with sand and mud. One of these plants (Sphe- 

 nopteris Mantelli, "Wonders of Geology," p. 370) 

 is characterised by its slender wedge-shaped leaf- 

 lets. The other fern (Lonchopteris Mantelli, lign. 21 ) 

 is the species already mentioned as occurring in 

 the greensand of Atherfield and Shanklin. It is 

 distinguished by its long and many-times pinnated 

 leaves, and the reticulated disposition of the 

 secondary veins that spring from the mid-rib of 

 the leaflets. 



Endogenites erosa. — In the strata of Tilgate 

 Forest, and in the sands at Hastings, numerous frag- 

 ments of the stems of a remarkable monocotyledon- 

 ous (?) plant occur, and are mentioned in my Fos- 

 sils of the South Downs, and figured in the Fossils 

 of Tilgate Forest, &c. These steins are of various 

 forms; some are cylindrical, and tapering at both 

 ends; and others are flattened, and of a clavated 

 shape, like some of the Cacti and Euphorbia ; the 



