516 STATE AND PROSPECTS OF ARBORICULTURE IN HAMPSHIRE, 
largest in area being the Osborne and Headon beds of the Fluvio- 
Marine series, where flourish the giants of oak and beech to the 
tiny bog myrtle (Myrica Gale). 
The geology of the Isle of Wight has been thoroughly explored, 
and little that would be of interest has been left to a chance 
observer. It consists of most of the formations found on the 
mainland, with others that have been brought to light by the 
action of the sea on the south coast, and by the investigations of 
savans and scientific men, who have been attracted here by the 
scenery and reputed salubrity of the climate to spend their leisure 
hours apart for a time from the busy world. 
A ridge of chalk forms the backbone of the island, commencing 
at Culver Cliff on the east, the breadth being about half a mile, 
running westward to Carisbrook Castle, where it begins to expand 
until it is about three miles broad; it then contracts again to 
about half a mile at Mottistone Down; it then strikes the sea at 
Compton Bay, near Freshwater, forming the coast line to the 
well-known Needles, which are also composed of chalk. Detached 
portions occur at Shanklin to Boniface Down, curving north to 
Appledurcombe House ; another small portion is at St Lawrence, 
and a third at St Catherine’s Hill. 
South of the chalk is to be found stretching along the coast 
from Cowleaze Chine to near Compton a band about a mile broad 
of the Weald clay, which is not found on the mainland, and 
which contains conglomerate sandstone, sandstone, various clays 
and marls. The whole of the undercliff consists of broken ground, 
the result of landslips and masses of rock fallen from higher 
levels, which, while contributing to the beauty of the scenery, 
have the effect of entirely concealing the underlying strata. This 
extends from Chine Head to Rocken End. The rest of the 
southern part is composed of the Lower Greensand, the Gault, 
and the Upper Greensand. 
To the north of the chalk ridge already described two narrow 
belts of plastic and London clays skirt the whole length of the 
chalk the same as on the mainland, then follow the Lower Bag- 
shot, Bracklesham, Barton clay, and Upper Bagshot, but in such 
a fitful manner that the dividing lines are scarcely distinguishable. 
The rest of the island north to the Solent and Spithead consists 
of the Osborne, Bembridge, and Hempstead beds, the first 
extending in a tkin line by the last formations, but in a broad 
belt from Newport on the east of the Medina river to Cowes, 
