528 Murchison' s Silurian System. 



Silurian rocks. " It was a very interesting task," observes Mr. 

 Murchison, " to trace the same strata from this narrow wedge 

 near Gamage Hall, through all their contractions and ex- 

 pansions between the new red sandstone and the old, to 

 their full development in the trough-shaped land to the 

 west of Newcut, and again to follow them till they finally 

 disappeared upon the sides of May Hill, where the new red 

 sandstone reposes at once on the old red sandstone and 

 Silurian rocks." Nor is this information without its econo- 

 mical importance. Attempts to raise coal at Newcut by spe- 

 culators, who were ignorant of the peculiar structure of the 

 district, ended in the ruin of all concerned. Nevertheless a 

 joint stock company was formed for renewing the attempts, 

 but without success. If coal works are ever to be renewed, 

 says Mr. Murchison, with any prospect of success, the trials 

 should be made to the east of Newcut, by sinking through a 

 thicker cover of new red sandstone than any hitherto pe- 

 netrated ; " for as it appears that the most important seams 

 on the west dipped to the east and south-east, so it is 

 possible that the measures may be found to have expanded 

 when followed upon their dip, &c." Mr. Murchison next 

 describes the north-western and eastern edges of the great 

 coal-basin of South Wales, and the parts of the basin more 

 immediately connected with the more ancient rocks, to which 

 his work is particularly devoted.* 



The rocks forming the northern and north-western escarp- 

 ments of this coal-basin are, Mr. M. remarks, of much 

 consequence in explaining the regular order and succession 

 of the strata between the carboniferous and Silurian systems ; 

 for these sections exhibit a full and unbroken sequence of 



* Mr. Murchison remarks, that the Rev. W. Conybeare is engaged 

 in the investigation of the great coal basin of South Wales, and there- 

 fore he has not himself attempted various descriptions of the members of 

 this coal-field in detail. 



