ROCKS OF SHROPSHIRE. 645 
a. The Wrekin Group. Lilleshall Hill, Ereal, Lawrence Hill, 
the Wrekin, Primrose Hill. 
b. Caer Caradoc Group. The Lawley, Caer Caradoc, the Ragleth, 
Hope Bowdler Hill. 
ec. Horderley Group. 
d. Kington Group. 
B. LirnorocicaAL AND STRATIGRAPHICAL CHARACTERS OF 
THE Rocks. 
1. Lilleshall Hill. 
This elevation is coloured on the survey map as “ altered Caradoc,” 
with a central boss of “greenstone.” I have seen no trace of 
greenstone or any other intrusive rock in the hill. The supposed 
Caradoc is of Precambrian age. 
Details—At the 8.W. end, in the road just below the village, is 
a hornstone of dark grey colour mottled with red. This is overlain, 
in a small opening immediately to the S.W. of the large quarry, by 
a grey thin-bedded ashy slate, with oval steatitic blotches on the 
planes of lamination, dipping N. 10° W. at 23°. In the great 
quarry there is a fine exposure of similar strata, much altered. 
Felspathic and steatitic matter are separated in the decomposition, 
and give in places a beautifully variegated appearance to the rock, 
pink and green colours predominating. Here and there the felspar 
has segregated in clusters and layers of red crystals. Some of the 
ashy beds are white and less altered. The general dip is N.N.W. 
at 30°. At the N.E. end of the quarry there is an interesting 
junction of the softer beds with an overlying hornstone. The latter 
is very hard and compact, approaching a hornstone ; while the 
former, in immediate contact with it, is so soft as to be easily 
scratched by the nail. In this place the ashy rock is very ferru- 
ginous, the iron peroxide separating in little round nests. The beds 
dip at 40°. The hornstone cannot be far from the horizon of a 
massive hornstone band which stands out as a craggy boss crowning 
the hill, and is probably the ‘‘ greenstone” of the Survey. N.E. of 
the summit, we have a repetition of grey ashy beds, dipping N. 10° 
W. at from 40° to 50°, succeeded by a felspathic breccia, composed 
of fragments of Wrekin rhyolite in a grey matrix. Some of the 
fragments show the characteristic banded structure. Breccias are 
abundant on the S.E. slope. The highest beds, clearly exposed in 
a long section at the N.E. end of the hill consist of alternations of 
ashy beds and hornstones, similar to those described, as represented 
in fig. 1. 
In this section the ashy bands are very clearly separated from 
the hornstones. ’ The beds 6 and d, for example, each about 10 feet 
thick, are soft and ferruginous, and have been excavated by weather- 
ing to a considerable depth ; while the band c, 5 feet thick, composed 
of hornstone precisely similar to the rock at the N.E. end of the 
great §.W. quarry, stands out like a sharp wall. 
