Prof. Lapivorth — Cambrian Rocks near Birmingham. 565 



with the Lickey quartzites, and their superiority to a series of slaty 

 and igneous rocks which rise out below the Trias of the neighbour- 

 hood of Caldecote. In addition, they also reached the conclusion 

 that the so-called Lower Carboniferous shales of Stockingford, which 

 overlie the quartzite, would be found to be also pre-Silurian in age. 

 The truth of this conclusion was demonstrated by the author the day 

 following, by the discovery of Cambrian LingulidcB, and subsequently 

 b}'^ the detection of many of the most typical Upper Cambrian 

 Brachiopoda and Trilobites within them, — identical with or repre- 

 sentative of the well-known species : — 



Acrotreta socialis, Linnrs. Kutorgina cingulata, Billings. 



Oholella Salteri, Day. Agnostus pisiformis, Linn. Var. 



Linr/ iilella ferruginea, Hicks. Lingulella Nicholsoni, Callaway. 



Within the same week Mr. Harrison detected similar Cambrian 

 shales upon the opposite side of the East Warwickshire Coalfield, 

 in the neighbourhood of Dost Hill, and elsewhere. 



The finest exhibition of these Cambrian rocks is that afforded by 

 the Nuneaton sections. Here our investigations show that a range 

 of country, ten or twelve miles in length by two miles in width, 

 is occupied by rocks of Upper Cambrian age. They fall into two 

 main divisions — a lower division of thick-bedded quartzite (Hartshill 

 quartzite), possibly 1,000 feet in thickness, and an upper division of 

 red, grey, and black shales, with abundant intrusions of hornblendic 

 trap, and having an apparent thickness of nearly 2,000 feet. 



The lowest zone of the quartzite is a coarse breccia, made up of 

 fragments of red and green felspathic rocks, slaty shales, and various 

 quartz porphyries. These have apparently been derived from an 

 older series of igneous and altered strata, a few beds of which may 

 be seen rising out from below the basal quartzites in the slopes near 

 Caldecote House, Nuneaton. 



The upper beds of the quartzite pass up by gradual intercalations 

 of argillaceous matter into the basement zone of the Stockingford 

 Shales. This zone consists of pui'ple mudstones crowded with 

 examples of small Brachiopoda of the genera Lingulella and Oholella. 

 The higher divisions of the Stockingford shales are grey and black 

 mudstones, filled with igneous intrusions, and faulted down in a 

 long-curved strike fault against the coal-bearing beds of the Upper 

 Carboniferous. 



The presumed basement-beds of the Lickey quartzite, as laid open 

 along the road between Rubery and Barnt Green, show included 

 fragments of igneous and fragmentary rock, identical with those of 

 the basement beds of the quartzite of Hartshill. A series of altered 

 purple and green felspathic rocks — breccias, and sandy shales — from 

 which these may possibly have been derived, has been detected by 

 the author, apparently rising out from below the Lickej'- quartzites, 

 at the southern end of the Lickey ridge, in the stream near Barnt 

 Green railway station. Similar rocks have subsequently been 

 detected at several neighbouring spots by other geologists — by 

 Messrs. T. S. Houghton, F. Martin, and Walcot Gibson. 



How these old pre-Cambrian and Cambrian ridges of altered and 



