506 Walcot Gibson — Carboniferous Rocks in iV". StaffordsJiire. 



liHve enabled Mr. C. B. Wedd and myself to make out the following 

 definite stratigraphical sequence in the Upper Carboniferous Eocks : — 



(4) Keele Sandstone Series. — Red sandstones and marls, calcareous 

 breccias, fossiliferous (Entomostracan) limestones. Thickness, 700 

 feet, summit nowhere seen. (=: Permian of older observers.) 



(3) Newcastle-under-Lyme Series.— Grey sandstones, marls, and 

 shales, with four thin coals. Two bands of fossiliferous limestone 

 (Entomostracan) form the base. Thickness, 250 to 300 feet. 



(2) Etruria Marl Series. — Red and mottled marls, with thin 

 bands of coarse green grit near the summit and base. Thickness, 

 700 to 800 feet. 



(1) Black Band Series. — Grey and mottled marls, the grey marl 

 predominating; bands of ironstone with Entomostraca, Anthracomya, 

 fish-remains ; occasional bands of grit 30 feet thick ; several thin 

 coals ; numerous zones of limestone and shales with Entomostraca. 

 A band of limestone, constant in position (36 to 40 feet) above the 

 Bassey Mine ironstone, forms the base. Thickness, about 250 feet. 



Yariability in the character of the deposits of the coal-measures 

 is universal, so that it is hardly to be expected that this sequence 

 will be recognizable in its entirety over the whole Midland area ; 

 but there can be no doubt that it is an important point to find out 

 which of these divisions occurs at the surface in the areas at present 

 regarded as Permian or as Upper Coal-measures on the published maps. 



Already the determination of the successive divisions above noted 

 has had important industrial bearings. The fact that the Newcastle 

 limestone lies at the base of grey measures intercalated between an 

 upper group of red strata (the Keele series) and a lower group of 

 red strata (the Etruria marls) has enabled me to detect true Upper 

 Coal-measures in Keele Park, Shutlanehead, and to the west of 

 Leycett. Moreover, there seems to be little doubt that the Coal- 

 measures of the Pottery Coalfield lie not far from the surface under 

 Little Madeley and Craddocks Moss. Evidence has been obtained 

 that the strata on the north-west side of the North Staffordshire 

 anticline do not uninterruptedly descend beneath red rocks (so-called 

 Permian) to tbe west of Leycett, but rise locally westward under 

 Hayes. The effect of this change of inclination is to bring to the 

 surface strata which lie considerably below the unproductive red 

 series, and to bring the principal coals and ironstones within reach 

 further west than might have been expected.^ 



It follows that a thorough and complete examination of the exposed 

 coalfields of the Midland counties and of the bordering New Red 

 rocks will be of the highest importance in determining at what 

 depth the productive measures lie beneath the great central tracts 

 of the Midland counties. 



^ See Summary of Progress of the Geological Survey of the United Kingdom for 

 1898, p. 123. 



