THK CAMIilMAN SYSTEM '.<.; 



The total thirkne.-> i> estimated at about 1500 feet and tl, 

 are clearly of Trcinadoc age. 



Passing again to Nuneaton, where the Hartwhill quart/ 

 succeeded by the Stockingford sliale.-, \ve have what a|.j 

 complete succession without break or faulting. 1'rofeaeor La] 

 has divided the shaly series into three group-, of whii-h the 

 following is a brief description, taking tin-in in defend iii K ' 

 order : 



Upper or Mcreval? Sl,<tt,'. -Only seen near Merevale, and . 



greenish-grey shales in which Dictyograpliu is abundant. The 

 thickness exposed may be 200 feet. 



Middle or OUllunj Shahs. Black shales, with some bands of grey shale ; 

 in highest beds are Sphccrophthalmus alntus ami ' 

 in the lower Agnostus pisiformis, Leptoplastus Salttri, Bryr 

 Aiujclini, and a Lingulella. Thickness probably 80o : 



i>r Parley Shales. Reddish-purple mudstODM and shale 

 some green and grey bauds, containing minute LimjuUllu, Obvltlla 

 sagittalis, Acrothele granulata, anda Conocoryirftr. Thickness about 

 600 feet. 



The fauna of the Purley shales is comparable with that 

 of the Conocoryphe exulans zone of Sweden, which belongs to th- 

 Paradoxides division and is homotaxial with our Menevian Series. 

 The black Oldbury shale.- are comparable with the black shale* 

 of Malvern and the Lower Dolgelly Beds. The Merevale shale* 

 appear to represent the lowest part of the Shineton shales and of 

 the Malvern grey shale. No horizon comparable with the mass of 

 Lingula flags has been recognised, but tin* may be due to tin- 

 scarcity of fossils in the lower part of the Oldbury shale*. 



3. Lake District and the Isle of Alan 



In the northern part of the Lake District around Skiddaw 

 Mountain, Derwent, and Crummock Waters there is a great thick 

 ness of dark-coloured slates, with bands of hard grit and occasional 

 beds of conglomerate. To these beds Sedgwick gave the name of 

 Skiddaw slates; the higher portion of them is of Ordovician 

 (Arenig) age, but the lower part is Cambrian (Trcinadoc and Lingula 

 Hags). The Cambrian age of this portion was *usj*-cted by Sedgwick 

 and maintained by Clifton Ward, but not until 1894 was Urn view 

 confirmed by good pahfontological evidence. 1 ' 



Mr. Ward took a certain band of grit occurring north of Skiddaw 

 as the base of the Arenig Series and identified with it certain flaggy 

 grits near Buttermere, but this has not U-en .<>u firmed and the 

 boundary line between Cambrian and Ordovician has not yet been 



