320 Prof. C. Lap worth — Cambrian Pocks at Nuneaton. 



Neighbourhood of Birmingham," in which evidences were adduced 

 demonstrative of the fact that the oldest sedimentary strata of the 

 Lickey Hills, and of the neighbourhood of the town of Nuneaton, 

 previously referred to the Llandovery and Carboniferous respec- 

 tively, are, in reality, of Cambrian age. Since that date these 

 Cambrian areas have been in part mapped by the members of the 

 Field Geology Class of the Mason College, and many confirmatory 

 and interesting points of detail have been detected by myself and 

 others. Some of these will be found incorporated in Mr. Jerome 

 Harrison's valuable paper on the " Pre-Carboniferous Floor of the 

 Midlands," published in the Midland Naturalist for 1885. 1 My friend 

 Mr. T. H. Waller, B.Sc, kindly undertook the microscopical 

 examination of the igneous rocks associated with these Cambrian 

 strata, but the results of his observations are as yet unpublished. I 

 hope to treat of the subject as a whole at the forthcoming Meeting 

 of the British Association, but as I have recently had to prepare a 

 general account of the Cambrian rocks of the Midlands for the local 

 "Association Guide Book," I have thought that a summary of my 

 conclusions as there laid down respecting the main fossiliferous area 

 of Nuneaton may be of present interest to other geologists working 

 among these rocks, and may serve as a point of departure for further 

 discussion and investigation. 



The largest area of Cambrian rocks in the Midlands is that of 

 Nuneaton and Atherstone in Eastern "Warwickshire. It extends 

 from the neighbourhood of Bedworth on the south to a point beyond 

 Merivale Park near Atherstone on the north, a distance of about 

 eight miles, and has a maximum width to the north of the hamlet of 

 Oldbury of about a mile and a quarter. On the eastern margin of the 

 Cambrian area its beds are overlain unconformably by the basement 

 beds of the Keuper Sandstone, around and to the south of the town 

 of Nuneaton. To the north of that town they are generally faulted 

 against the Keuper Marl, but are locally overlapped by some of its 

 basal beds. On the western side the Cambrian rocks are overlain 

 unconformably by the lowest sandstones of the East Warwickshire 

 Coalfield, but there appear evidences of faulting between the two 

 systems in some localities. 



The sequence of the rocks of this Cambrian area is as follows : — 



A. Caldecote Volcanic Rocks. 



(1) A thin series of volcanic ashes, beautifully stratified, shown 

 in an old cutting (The Tunnel) a few yards to the north-west of 

 Caldecote Lodge, and forming the lowest rocks exposed in the 

 Nuneaton district. 



(2) Quartz-felsite and diabase-porphyrite, seen in an old quarry 

 about a quarter of a mile south-east of Caldecote Lodge. The quartz- 

 felsite is often brecciated in character, and is doubtfully intrusive in 

 the Caldecote ashes. The diabase-porphyrite is subsequent in age to 

 the quartz-felsite, resting upon it, making its way into it in veins 

 and strings, and including fragments of the quartz-felsite caught up 

 in its flow. 



1 Harrison, Midland Naturalist, 1885, vol. viii. pp. 38 — 69 el seq. 



