a6() 



DESCENDING 



Maximu m 



approxlnukte 



thickness. 



Carboniferous Lime- 

 stone. 



Old Red Sandstone. 



I, Ludlow Bocks. 



Feet. 

 500? 



10,000. 



2000. 



Subdivisions. 



Limestone. Shale. 



a. Red conglomerate 

 and sandstone. 



h. Cornstone and argil- 

 laceous marls. 



c. Tile stones, &c. 



d. Upper Ludlow rock. 



A vmestry and Sedge- 

 ley limestone. 



/. Lower Ludlow rock. 



Lithological Characters. 



a. Quartzose conglomerate over- 

 lying thick-bedded sandstones. 



b. Red and green, concretionary 

 limestones, with spotted argil- 

 laceous marls and beds of 

 sandstone. 



c. Flaggy, highly micaceous, 

 hard, red and green sandstone. 



d. Slightly micaceous, grey-co- 

 loured, thin-bedded sand- 

 stone. 



e. Subcrystalline or grey and 

 blue argillaceous limestone. 



/. Sandy, liver, and dark- co- 

 loured shale and flag, with 

 concretions of earthy lime- 

 stone. 



II.WenlockandDud-J 

 ley Rocks. \ 



1800. 



g. Wenlock and Dud- 

 ley limestone. 



h. Wenlock and Dud- 

 ley shale. 



g. Highly concretionary grey 

 d blue subcrvstalline lime- 



an( 

 stone. 



A. Argillaceous shale, liver and 

 dark gray- coloured, rarely mi- 

 caceous, with nodules of earthy 

 limestone. 



III. Horderley and \ 

 May Hill Rocks 



2500. 



«. Flags. 



k. Sandstones, grits, 

 and limestones. 



i. Thin-bedded, impure, shelly 

 limestone, and finely lamina- 

 ted, slightly micaceous green- 

 ish sandstone. 



k.* Thin-bedded, red, purple, 

 green, and white freestones. 

 Conglomeritic quartzose grits, 

 Sandy and gritty limestones. 



IV. Builth and Llan- 

 deilo flags. 



1200. 



V. Longmynd and 

 Gwastaden Rocks. 



Many 



thousand 



feet. 



/. Dark-coloured fl 

 calcareous, with 

 stone and schist. 



igs, mostl 

 some san 



t 



Comprising all the slaty 

 system of South 

 Wales. 



m. Hard, close-gram ed, gray 

 greenish and purple sand- 

 stone. Red and gray quart- 

 zose conglomerate. Slate-co- 

 loured and purple schists. 

 Coarse slates : little or no 

 calcareous matter. 



« The sandstones (i, k, and m,) pass into quartz rock in the vicinity of certain trap rocks (Wrekin, Caer Caradoc, Blaen 

 PylVrin Ram, Uc.,) as will be explained in the Work alhwlcd to. 



