448 J. Prestwich, Esq., on the 



lowing divisions; only the three lower of which occur in the immediate 

 neighbourhood of Coalbrook Dale. 



Foreign Appellations. 



1 . Red and Green Marls Keuper and Marnes irisees. 



2. Sandstones and Conglomerates Bunter Sandstein and Gres btgarre. 



3. Calcareous conglomerates Zechstein and Calcaire magnesien. 



4. Lower Red Sandstone Rothe Todte Liegende. 



At Rowton Farm, near Caughley, are exhibited alternating strata of gray, 

 mottled, liver-coloured shales and marls, of a dark red tenacious clay, and of 

 coarse dark-brick red, and light gray, micaceous sandstones, sometimes finely 

 conglomeratic, belonging to the lower red sandstone (No. 4.). Owing to the 

 numerous faults which surround and cut off the coal-measures^ the relation of 

 that formation to the new red sandstone cannot be satisfactorily ascertained. 

 The dip of the two formations generally appears to be in the same direction ; 

 and, in the south of the field, the lithological characters of the upper strata of 

 the coal-measures so closely resemble those of some of the lower beds of the 

 new red sandstone, that the latter might, in many cases, be mistaken for 

 coal-measures. Imperfect impressions of the leaves of soft, monocotyle- 

 donous plants occur, though rarely, in some of the sandstone beds. The 

 characters, here exhibited by this portion of the red sandstone, offer the 

 greatest analogies to those of the lowest beds of the deposit in the north of 

 England, as described by Professor Sedgwick, in his able memoir on the 

 Magnesian Limestone*. 



Upon this lowest division repose thick strata of characteristic brick-red and 

 yellowish sandstones, with a few subordinate beds of calcareous conglomerate 

 (No. 3.), composed of angular and slightly rounded fragments of limestone, 

 which contain characteristic fossils of the mountain limestone, and are imbed- 

 ded in a red, arenaceous cement. These equivalents of the dolomitic con- 

 glomerate are rarely visible. 



In Apley Park, and in a field between the Windmill and Homer Farms, 

 they were formerly quarried ; and it is probable that a thin, irregular zone of 

 them may range parallel to the eastern boundary of the coal-measures ; but, 

 owing to the abundance of limestone at Lilleshall and Steeraways, the conglo- 

 merate is not sought after. At Homer Farm, the sandstones of this division 

 are brought very near to the coal-measures, and along the line of the boun- 

 dary fault, they appear, in many places, to be in immediate contact with the 

 carboniferous and trap rocks. 



To this division succeeds a considerable thickness of bright red sand- 

 stones, mottled marls, and coarse conglomerates (No. 2.), which are interesting, 

 * Geological Transactions, 2nd Series, Vol. III., p. 37, et seq. 



