536 Murchison's Silurian System. 



rock, is a subject that must be decided by the observations 

 of geologists in India. 



We shall endeavour to put the Indian student in posses- 

 sion of the principal details brought together by Mr. Mur- 

 chison in that part of the British isles of all others best 

 calculated to afford the true distinguishing peculiarities of 

 the old red system as it occurs in the western world. " The 

 enormous thickness of the old red sandstone, included be- 

 tween the coal measures and Silurian rocks, will at once be 

 comprehended by any observer who places himself on the 

 eastern slopes of the latter near Kington, and casting his eye 

 to the south-east, the circle of vision although extending over 

 all the mountains between the Wye and the Usk, and termi- 

 nating only in the Brecon mountains and Carmarthen ferns, 

 embraces nothing but old red sandstone ; nor does this view 

 include a wide superficies occupied merely by undulating 

 masses of the same strata, but a territory, in which succes- 

 sive members of the system rise from beneath each other in 

 distinct mountainous escarpments." Nor is Mr. Murchison's 

 observations confined to this field, they are also extended to 

 Shropshire, where a similar succession of the old red sand- 

 stone is displayed, as well as to Herefordshire, where the same 

 rocks compose a great basin, the lower strata of which are 

 turned up on both banks against Silurian rocks. 



This ample field may be taken as the fairest example 

 presented by the old red system in Europe ; and Mr. Mur- 

 chison's observations afford not only the latest, but the 

 safest standard with which to compare the results of our 

 observations on such rocks in India, as far as they appear to 

 be representatives of the old red sandstone in Europe. Mr. 

 Murchison divides the old red system into three divisions, 

 as follows — 



1. Quartzose, conglomerate, and sandstone. 



2. Cornstone and marl. 

 S. Tile stone. 



