Page:VCH Worcestershire 1.djvu/36

 A HISTORY OF WORCESTERSHIRE ently been thrust on to the Cambrian quartzite, and the overthrust series has been subsequently folded along a north-and-south axis, together with the Old Red Sandstone. He adds that the Coal Measures were subse- quently deposited unconformably on the faulted and folded series, while in later times the old rocks covered by the Trias were let down on the eastern side. Thus ' we appear to have in this small area an epitome of the history of the Malvern and Abberley Ranges.'^ Near Barnt Green Junction, towards the southern end of the Lickey Hills, there is an inlier of ancient tuffs and volcanic grits ; rocks described by Prof. Lapworth as probably deposited in water during a time of contemporaneous igneous action. They comprise also green, grey and purple, flaggy and micaceous shaly beds, penetrated by diorites. These Barnt Green rocks are apparently overlain by the Cambrian Lickey quart- zite, but, as Mr. Walcot Gibson remarks, 'the actual relations of the two formations are not visible.' ^ CAMBRIAN Practically speaking the Cambrian rocks are the oldest known fossil- iferous strata, for the obscure records, at present found in earlier sediments, simply indicate that life existed. In the Cambrian period, however, we find evidence, not merely of fucoids, sponges, and worm-burrows, but of bryozoa, brachiopods, mollusca, and notably of trilobites. The Cam- brian rocks have proved to be locally divided into, — M ,.,„,„ cuoi c / Grey Shales with Dictyonema sociale. alvern Shales i m, cu i ■ u /-v/ (. hlack Shales with Olenus. Hollybush Sandstone with conglomerate and quartzite at base. The Hollybush Sandstone is a greenish, micaceous sandstone, occa- sionally calcareous, and it contains at its base pebbles which have been derived from Archaean rocks. Upon these it probably in some places rests unconformably, although the junction, according to Prof. Groom, is mainly a faulted one. It occurs in a highly inclined position at White- leaved Oak, to the south of Raggedstone Hill (839 feet high), and along the western borders of that hill and Midsummer Hill (937 feet). For many years only obscure worm-tracks and fucoidal remains had been found in the Hollybush Sandstone, but there have now been recorded remains of the brachiopods, Kutorgina cingulata and Obolella salteri, and of the pteropod Hyolithus. The pebbles in the Hollybush conglomerate differ in character from any of the local Archxan rocks, and thus support Prof Groom's view that the Malvern Hills did not form a coast-line in Cambrian times.' The Malvern Shales overlie the Hollybush Sandstone, and in the lower (black) portion a number of trilobites occur, such as Peltura ^ Groom, Quart. Journ. Geol. Sac, vol. Ivi. p. 163 ; see also C. St. A. Coles, Geol. Mag., 1898, p. 304 ; and Symonds, Records of the Rods, p. 38. ^ See Lapworth, Proc. Geol. Assoc., vol. xv. p. 328 ; and Gibson in Summary of Progress of Geo/. Survey for 1897, p. 67. ' Rep. Brit. Assoc, for 1900. 6