Affinity between Bafaltes and Granite. 6 5 
generally rugged, points, riling over the face of Shropfhire 
and the adjacent counties. Were the plains covered with 
water a few yards in depth, thefe eminences would appear 
from diftance to distance like fo many ftepping ftones. They 
all, except the Malvern Hills, which, though compofed of 
granite, I confider as part of the fame fyftem, confift of whin- 
ftone. Among thefe ftepping ftones I reckon the bafaltic hills 
near Welfhpool, the Wrekin, Lillefhall Hill, and, at a greater 
diftance towards the Eaft, the rifing grounds near Newcaftle in 
Stafrordftfire, whence the whin rock, perhaps, communicates 
by the toadftone of Derbyfliire, through the hills in the North 
of England with the whinftone towards the South of Scot- 
land. In a fouth or fouth-weft diredtion from the Wrekin, a 
number of craggy eminences arile. They are bafaltes, and 
form a ftriking contraft with the fmooth, rounded, and 
lumpifti fwells of fchiftus in their neighbourhood. From the 
whin rocks near Stretton we may pafs by the Brown and 
Titterftone Clee Hills (on the latter of which are regular prif- 
matic columns) to the Malvern Hills. About thefe hills lie ftrata 
of fchiftus and limeftone, as is feen 011 the road from Much 
Wenlock to Stretton. To the fouth*eaft an extenfive field of 
whinftone, with occafional elevations, is fpread over the confines 
of Worcefterlhire, Warwickfhire, and Staffordfhire. Here we 
have the Rowley ragftone. Whether the bafaltes proceeds 
fouthward by fuch interruptions till it join the Elvin or 
whinftone, and granite of Devonfhire and Cornwall, where 
I imagine they may be found incorporated, I wi(h for an 
opportunity to examine. In the plain part of this whole 
diftrlft, the whin rock appears frequently at the furface, or 
a little below the ftrata, fo that the hills have probably a fub- 
terraneous communication with one another, and there needed 
Vol. LXXXI. K but 
