316 Reviews — H.B. Woodward's Geology of England and Wales. 



weigM to his conclusions. " The relations between the Old Eed 

 Sandstone and the underlying Silurian and overlying Carboniferous 

 rocks have been long since established. In both instances a perfect 

 conformity exists. But only in recent years has it been fully 

 realized that there is a great unconformity between the Upper and 

 Lower Old Red Sandstone." In the Devonshire area there is a con- 

 formable sequence in the strata, and the Middle Devonian (marine) 

 bridges over the interval between the Upper and Lower Old Red 

 Sandstone in Wales, etc. In Scotland also, as pointed out by Dr. 

 Geikie, the Old Red Sandstone must be placed in two divisions with 

 a complete discordance between the two, the lower passing con- 

 formably into the Silurian, the Upper graduating into the Carbon- 

 iferous. In the district of the Cheviot Hills, however, owing to the 

 accumulation of volcanic material, a marked discordance is shown in 

 Mr. Goodchild's section (fig, 16) between the "Cheviot Series" 

 (Lower Old Red Sandstone) and the underlying Silurian, but this 

 is evidently an exception. 



When a system is thus weakened by internal discordance, whilst 

 its extremities exhibit a disposition to amalgamate with their respec- 

 tive neighbours, a period of annexation seems to be at hand. At 

 present the fossiliferous Devonian maintains a firm front against all 

 comers, though there are not wanting geologists who would hand it 

 over to the Silurian by way of compensation for the loss of the 

 Ordovician rocks. 



Grouping the Upper Old Red Sandstone with the Carboniferous 

 System, the latter is held to comprise the following formations : — 



Upper ( Coal Measures. 



Carboniferous. 1 Millstone Grit. 



Lower 

 Carboniferous. 



^ Upper Limestone Shales and Toredale \ 



Rocks. I Bernician and Calci- 



Carbonif erous and Mountain Limestone. > f erous Sandstone 

 Lower Limestone Shales and Tuedian \ Series. 



Beds. / 



Basement Conglomerate and Upper Old 



Eed Sandstone. 



Nearly sixty pages are devoted to this most important system, and 

 there are nearly a dozen sections, by way of illustration, from 

 various authors. To begin with, there is a very effective section by 

 J. W. Davis, showing the separation of the Yorkshire from the 

 Lancashire Coal-fields by means of the Pennine anticlinal. The 

 various " edges " of the Millstone Grit on the Yorkshire side are 

 particularly well brought out. This originally appeared in the 

 Geol. Mag. (1878, p. 504) in a paper on the Valley of the Calder. 

 The following sections also occur : — Draughton Quarry near Skipton 

 (Dr. C. Ricketts), to show contortions in the Carboniferous Lime- 

 stone ; across the Eglwyseg Rocks, Denbighshire (Prof. A. H. Green), 

 to show an ascending sequence ; across part of Charnwood Forest 

 (Prof. E. Hull), to show Carboniferous strata lying on the edge of 

 the older rocks ; across the Mendips (H. B. W.), to show position of 

 the Carboniferous rocks on either side of the anticlinal ; across 

 Ingleborough (J. G. Goodchild), to show relations of the Carbon- 



