652 C. CALLAWAY ON THE PRECAMBRIAN 
Summary.—The Wrekin is a 8.W. ridge, composed of alterna- 
tions of bedded felspathic lavas and tuffs, with an average dip of 40° 
to the N. and a little to the W. of N., broken through and dis- 
turbed in one place by a mass of greenstone sending off dykes to 
the N.E., and flanked on both sides by quartzites, which on the 
S.E. are succeeded by the Hollybush Sandstone and the Shineton 
Shales. 
5. Primrose Hill. 
The Wrekin tuff is continued through the saddle connecting this 
spur with the Wrekin mass, and appears on the northern slope near 
the summit. The chief part of the hill is composed of rocks of an 
entirely different type. On the 8.W. slope, about twenty yards 
below the top, crops out a band of schistose rock dipping to the 
N.E. at 55°. It is a very quartzose granulite, the quartz being 
sometimes quartzite, and the felspar is like the red variety in the 
Ercal quarry. It is very irregular in composition, passing frequently 
into hornblendic gneiss, and sometimes approximating to a quartzite 
with a little red felspar. The W. andS8.W. slopes are occupied with 
granitoidite *, which appears to Prof. Bonney and myself identical 
with the red rock of the Ercal (Note C). On the N.W. side crop out 
numerous exposures of a compact rock, which Prof. Bonney has 
determined to be clastic and similar to hornstone. Some eruptive 
rocks break out in a few places. Amongst these I have observed a 
diorite, undistinguishable from a specimen in my collection from 
Malvern; and Prof. Bonney confirms this view (Note C, p. 665). 
Some of the granitoidite also is of the Malvern type, showing the red 
felspar and the small nests of mica, sometimes in a decomposed state, 
characteristic of the granitic type which I have from the Wych and 
the North Hill. In both localities there is also the same tendency to 
pass into hornblendic rock. Thestrike of the beds is also the same. 
On the whole, I have no hesitation in identifying the Primrose- 
Hill rocks with the Malvernian system. Further attempts at cor- 
relation are postponed to a future paper. The Wrekin tuffs are in 
contact with the older schists N.E. of the summit of Primrose Hill, 
and the plane of separation is undoubtedly a fault. The discord- 
ance of strike between the two groups suggests a considerable un- 
conformity. 
6. The Wrockwardine mass. 
Details.—The prevailing rocks of this area are purple and green 
felstones and breccias. At the village of Wrockwardine, green is 
the predominant colour. In one or two spots a greenish dolerite, 
highly decomposed and containing free calcite, has pushed its way 
up to the surface. In the lane leading from the village towards 
Cluddley are several exposures of rock like hornstone, and on a 
knoll to the K. of this road are purple felstones, whose clearly 
developed banding shows a 8.W. strike with a prevailing S.E. dip. 
* IT adopt this term from Prof. Bonney, Quart. Journ. Geol. Soc. vol. xxxy. 
p- 322, note *, 
