48 
ERRATIC BLOCKS. 
ERRATIC BLOCKS OF SANDSTONE. 
Immense blocks and boulders of siliceous sand- 
stone, composed of granular quartz, and occasion- 
ally enveloping chalk flints, and other extraneous 
bodies, lie scattered over the Downs, and on the 
ploughed lands, near Brighton, Falmer, and other 
places. This sandstone is perfectly analogous to 
that which occurs in Berkshire and Wiltshire, 
where it is distinguislied by the provincial term of 
“ Grey PF'eathers.'’ Of this substance, Stonehenge, 
and other druidical monuments are composed, — 
a circumstance that has given rise to its present 
geological appellation. The cement of the beauti- 
ful conglomerate or puddingstone of Hertfordshire, 
agrees in its characters with the druid sandstone, 
and from that breccia also occurring in detached 
blocks above the chalk, it is now generally sup- 
posed that they are both of contemporaneous 
origin ; the siliceous deposition, when it did not 
envelojDe any foreign substance, forming the rock 
called the “ Grey TJ^eathers,’’ and when it fell 
among pebbles of any kind, composing a breccia 
or 2^ udd ing stone. * 
The puddingstone is exceedingly rare in Sussex, 
but specimens sometimes occur ; and several ex- 
amples have been found in the vicinity of New- 
haven, that could not be distinguished from the 
Hertfordshire breccia. 
Examples of the siliceous sandstone may be seen 
on the hill near Lewes B ace-course ; at Bonner ; 
* Geological Transactions, vol.ii. p.225. 
