490 Geological Society. 



into the lower new red sandstone. Besides the open works formerly 

 alluded to by him in previous memoirs, Mr. M. now states, that his for- 

 mer conjectures respecting the passage of the 1 0-yard coal beneath the 

 new red sandstone which flanks it on the east and west have been ve- 

 rified by the efforts of the Earl of Dartmouth, who, after sinking to a 

 depth of 13 1 yards tlirough strata of the lower new red sandstone, has 

 very recently succeeded by further borings, carried down to the depth 

 of 290 yards, in discovering tiie 1 -foot, 2-foot, and "Brooch" coal 

 seams, which overlie the 10-yard coal throughout the Dudley field. 

 These operations have taken place at Christchurch, one mile beyond 

 the superficial boundary of the coal-field. 



Besides the plants so common in all carboniferous tracts, the author 

 has observed the presence of animal organic remains. Unios of several 

 species are abundant; and in the northern or lower part of the field 

 he has extracted fragments of fishes, which have been named by Pro- 

 fessor Agassiz, 



Megalichlhijs HibhertVi, 



M. Saurouies, 



Diptodtis gibbus ; 

 together with scales, coprolites, &c., proving an identity between the 

 animals deposited in these coal measures and those of Edinburgh, de- 

 scribed by Dr. Hibbert. The same species, it will be recollected, have 

 been pointed out by Sir Philip Egerton as occurring in the N. Stafford- 

 shire coal-field, and one of them has been observed by Mr. Prestwich 

 in the coal-field of Coalbrook Dale. Mr. Murchison, however, re- 

 marks that he has not yet observed any marine remains in these coal 

 measures similar to those of Coalbrook Dale ; and nothing ye^ found 

 can invalidate the inference that the coal of Dudley and Wolverhamp- 

 ton may have been accumulated exclusively in fresh water. 



h. Silurian rocks. — The mountain or carboniferous limestone and 

 the old red sandstone, which in so many other parts of England form 

 the support of coal tracts, being wanting, this field reposes directly 

 on rocks which Mr. Murchison proves to consist of the two upper 

 members of the Silurian system, viz. "the Ludlow rocks" and " Wen- 

 lock limestone."* As, however, these rocks rise up irregularly, like 

 separate islands, through the surrounding coal measures, and not in 

 their regular order of superposition, so it was obviously impracticable 

 to have determined their relative age by any local evidences ; and hence 

 no attempts could have been made to distinguish the younger from the 

 older deposits, until the structure and organic remains of the different 

 members of the Silurian system, had been fairly worked out in other 

 districts, where these types were fully and clearly displayed in their 

 regular order. 



2. Ludlow rocks. — These rocks appear at the surface in three de- 

 tached points in this coal-field, viz. Sedgeley, Turner's Hill, and the 

 Hayes. At Sedgeley they are thrown up in an elongated ellipse, very 



* There is one spot, however, within the author's knowledge where the 

 •inderp;round works reached a thick mass of red shale or marl beneath tlie 

 coal-ficUl ; but the works liaviiig been long abandoned, no correct kiiow- 

 iedge of these red rocks can be now obtained. 



