GEOLOGY 



Period 



Formation 



Character of the strata 



Approximate 



thickness 



in feet 



Recent 



Alluvium 



Gravel, sand, loam, clay, and 



peat, along present streams . up to 2O ? 



Pleistocene 



Brickearth, Valley Gravel 

 Glacial Drift . 



Loam, sand, and gravel of old 



river-courses up to 2O ? 



Sand, gravel, stony clay ; 



boulders of distant rocks . up to i oo ? 



Jurassic 



Great Oolite Series . 

 Inferior Oolite Series. 



f Upper . . . 

 Lias ] Middle. . . 



V Lower . 



Oolitic limestones and clays, 



with sandstones . . . . 80 to 100 

 Oolitic limestones, with sands 



and calcareous sandstone . 80 to 1 50 

 Clay and shale, with limestones 



and calcareous sandstones . 120 



Hard ferruginous limestone, 



sands and shales .... 280 



Clays and shales, with clayey 



limestones in lower part . up to 960 



Rhaetic 



Marl 



Keuper 



Triassic 



Bunter - 



Sandstone 

 Upper . 

 Middle. 



? Lower 



White and grey limestones, dark 



shales, and yellow sandstone 

 Red marl, mottled green ; 



green and buff (20 to 30 



feet) at summit .... 

 Red and brown sandstones and 



marls 



Fine red sandstone, without 



pebbles 



Pebbly red sandstone, with 



pebble-beds 



Yellow sandstone, without 



pebbles 



' Permian ' of Salopian type . 



Car- 

 boniferous 



Coal Measures- 



Newer (barren) 

 measures . 



Older (produc- 

 tive) measures 



Red sandstones and marls, with 

 limestone-conglomerate . 



Sandstones and shales, with 

 brick-clays and Spirorbis 

 limestones 



Sandstones and shales, with 

 seams of coal, ironstone, and 



30 to 40 



600 to 700 

 150 to 200 



200 

 250 to 350 



2,000 



I,OOO 



fireclay , 



Cambrian 



Upper : Stockingford Shales 

 Lower : Hartshill Quartzite 



Grey, black, and purple shales 2,000 

 Grey quartzites and sandstones, 



with purple and grey shales 



and a thin limestone. . . 600 



Archaean 



Uriconian and Upper Long- 

 myndian. Caldecote series . 



Volcanic breccias, tuffs, and ~\ ? several 

 grits ) hundred 



/Diorites(Camptonites) ; 

 Intrusive post -Cambrian but 

 Igneous ! pre-Carboniferous 

 Rocks Porphyritic Basalt ; of 



V. pre-Cambrian age . 



Of -various 

 ages 



[Crystalline igneous rocks 



