HORSTED SAND. 191 
tlie Strata appear in tlie following succession, dip- 
})ing towards the south-west ; — 
1. Sand and sandstone, ferruginous. 
2. Grey sand, with minute particles of lignite. 
3. Sandy marl. 
4. Sand and sandstone, highly ferruginous. 
5. White sand and sandstone. 
The Horsted sand and loam occur along the 
northern border of the Weald of Sussex, and the 
southern of that of Kent. 
'FUgate Beds. — Beneath the Horsted beds irre- 
gular alternations of sand and sandstone succeed ; 
the lowermost stratum conUiining large concretional 
or lenticular masses of a compact calciferous grit or 
sandstone, which was formerly extensively quarried 
in the neighbourhood of Tilgate and St. Leonard’s 
forests, near Horsham. * The lower portions of this 
bed in some localities form a conglomerate, and 
contain pebbles of quartz and jasper, some of which 
may be of chemical origin, but others have evident- 
ly been transported from a distance. There are 
three or four layers of the Tilgate stone, varying in 
thickness from 2 to 3 inches, or to 2 feet each. 
These beds rest on blue clay and shale, which 
separate them from the next subdivision. They 
are the principal repository of the saurian remains 
of the waters which deposited the Hastings sands, 
and are therefore by far the most interesting strata 
of the formation. They extend from its western 
* Tliese strata were first described by the author in a paper read 
before the Geological Society, in the beginning of 1822; and further 
noticed in the “ Fossils of the South Downs ; ” and also in a memoir 
read before the Geological Society of London, in June, 1822. 
