﻿312 J. E. Dahjns — Prof. Hull's Carhoniferous Classification. 



some instances, too hastily arrived at in the earlier days of their 

 work, before time and experience had shown the necessity of that 

 habit of caution and hesitation which is forced upon a field -geologist 

 more and more as he pursues his work, and which might have pre- 

 vented such inconsistencies as are illustrated by the case of the 

 " Eotherham Eock," as it is mapped in two different editions of the 

 One-inch Survey Map ; or by such a statement as that of Mr. Aveline 

 himself that "a peculiarity of the [Lower Bunter] sandstone is, that 

 it is quite free from the pebbles that characterize the formation over- 

 lying it," when a little closer observation might have shown him 

 some half-a-dozen sections within easy reach of Nottingham, in which 

 the pebbles of quartz, quartzite, slate, and grit, are scattered sparsely 

 through the sandy matrix. But these are of course petty matters of 

 detail, worthy only of the attention of that inferior order labelled by 

 Mr. Aveline "local geologists," one of whom has observed a good 

 many of the pebbles in question even in the typical section of Lower 

 Bunter south of Mansfield, which Mr. Aveline refers to in his 

 "Memoir" (p. 12). 



I will not intrude further upon your space and your courtesy, 

 except to disclaim, on my own part and that of my co-workers in 

 the same field, any wish to make an attack upon Mr. Aveline or any 

 of his colleagues (several of whom I have the honour and the pleasure 

 to know personallj') ; while, on the other hand, he, no doubt, would 

 be the last to repudiate the notion, that, with all their exceptional 

 advantages, they possess a monopoly of geological knowledge. We 

 have on both sides a strong desire to arrive at the actual truth ; and, 

 even if further investigation should prove our position to be alto- 

 gether iintenable, I shall, for my part, be glad, if I have in any way 

 helped to bring this question into the full light of criticism. 



VL — On Peofessob. Hull's Carboniferous Classification. 



By J. R. Dakyns, M.A.; 

 of Her Majesty's Geological Survey. 



N a paper read before the Geological Society of London, Prof. 

 Hull proposes, as generally applicable to the whole of Great 

 Britain and Ireland, a new classification of the Carboniferous rocks, 

 as follows : 



Uppek Cahboniferous Group. 



Stage G. Upper Coal-measures ) Essentially 



,, F. Middle Coal-measures ... ... ... \ freshwater. 



Middle Carboniferous Group. 



Stage E. Lower Coal-measures or Ganister Beds 1 



,, D. Millstone-grit Series > Essentially marine 



,, C. Yoredale Series ... ) 



Lower Carboniferous Group. 



Stage B. Carboniferous Limestone Series \ Essentially marine 



,, A. Lower Shales, Slates, Carboniferous, Cal- > (except in Scot- 

 ciferous and Sandstone Series ... ) land). 



There are two points in this classification : one is the division of 

 the whole Carboniferous Series into two portions, distinguished as 



