376 Geological Society, 



GEOLOGICAL SOCIETY. 



Feb. 4. — A paper was read, " On certain Coal Tracts in Salop, 

 Worcestershire and North Gloucestershire," by Roderick Impey 

 Murchison, Esq. V.P.G.S. 



Pursuing the inquiry in descending order, commenced at the last 

 Meeting, the author calls attention to certain undescribed carboni- 

 ferous districts, the outlines of which he has laid down upon the 

 Ordnance Maps. 



I. " Shrewsbury or upper Coal-measures with Jreshivater Limestone." 

 The author takes this opportunity of showing, that the coal- 

 measures near Shrewsbury, which he formerly described* as con- 

 taining a subordinate band of lacustrine limestone, pass up con- 

 formably into the lower member of new red sandstone, and are thus 

 proved to constitute the uppermost portion of the carboniferous 

 series. He has this year discovered this freshwater limestone (with 

 the same minute Planorbis, &c.,) in a thin zone of coal-measures 

 extending from Tasley near Bridgnorth to Coughley near Broseley, 

 where the strata, like those near Shrewsbury, also dip conformably 

 beneath the lower new red sandstone. Mr. Prestwich has ascertained 

 that some of the great beds of coal of the Broseley and Colebrook- 

 dale field are worked beneath this limestone. 



II. Western Coal-Jield of Salop. 



The Oswestry coal-field, lying on the western borders of Shrop- 

 shire, is completely separated from that of Shrewsbury, and is the 

 southern termination of the carboniferous zone, which extends from 

 Flintshire by Ruabon and Chirk. It is of small extent, and little 

 productive, containing only one bed of good coal. The millstone 

 grit, which rises from beneath it on three sides, is remarkable for 

 containing beds of cherty breccia, courses of sandy, encrinital lime- 

 stone, and in the lower portion strata of thick-bedded, red sandstone, 

 in parts undistinguishable from the new red sandstone. The carbo- 

 niferous limestone beneath this red sandstone, is exhibited on a very 

 large scale in the fine escarpments of Llanymynech, Porth-y-wain 

 and Treflach. The upper part is somewhat magnesian, and con- 

 tains few fossils, with thin veins of copper ore; the lower is a fine 

 subcrystalline limestone, in which are found Producta hemisjphcBrica, 

 the large basaltiform Coral, and many other fossils characteristic of 

 the formation. Faults are numerous, and in the principal one run- 

 ning from north by east to south by west, the coal is upcast 180 

 yards. These dislocations increase as they rise upon the hill sides, 

 and decrease as they range towards the plains of Shropshire. 

 III. " Central and Southern Coal-fields qf Salop T 



The author mentions that he has accumulated many new facts 

 respecting the coal-fields of the Clee Hills, since his communications 

 in 1832, the principal of which are. That at the Titterstone Clee, the 

 new works established by Mr. Lewis, have proved the existence of 

 productive coal seams under the Hoar Edge, on the western side of 



* Geol. Proceedings, vol. i. p. 472. 



