508 Notices of Memoirs—W. H. Hudleston— | 
the Old-Red of the Welsh border does not differ from the 
Devonian of Devonshire more than does the Carboniferous of Wales 
from beds of the same system in this county. The Culm-measures 
are something sui generis, and it seems difficult to account for their 
origin. 
It may be worth mentioning in this connection that Dr. Barrois, 
speaking of the physical history of Brittany, which presents certain 
analogies with that of our south-western peninsula, observes that the 
Carboniferous period in that region was one of oscillation between 
terrestrial and marine conditions—a period of extensive eruptions 
and great earth movements. Hence he says that a considerable 
portion of the sediments, especially towards the base, are of volcanic 
origin. This is not at all the case with the Carboniferous in North 
Devon, where the sequence is undisturbed. According to the views 
generally accepted, the main horizon for contemporaneous igneous 
rocks in the Paleozoic of Devonshire lies in the Lower Devonian, 
though there seems to be some difference of opinion upon this point, 
THe OLD-RED oR DEVONIAN QUESTION. 
This may with justice be termed the home question ; but in order 
to attempt a solution, it will be found necessary, in the first instance, 
to take into consideration the Old-Red Sandstone of other areas. 
The claim of the Devonian to recognition as one of the great 
geological systems has been challenged more than once; and even 
when this has not been disputed, there have been divers contradictory 
efforts to fit in the marine Devonians with the several members of 
the Old-Red Sandstone. In North Devon the matter was further 
complicated by the great Jukesian heresy, based on the alternative 
supposition of a concealed anticlinal with an inversion towards the 
north, or more probably an east and west fault. These ideas, as 
you know, were successfully combated by Mr. Etheridge and Mr. 
Townshend Hall in the earliest days of the Association; and about 
ten years ago the latter gentleman reviewed the history and classifi- 
cation of the North-Devon Rocks in an able paper which appeared 
in the “Transactions.” His own classification of the North-Devon 
beds differs in details from that adopted by Ussher and Woodward ; 
but this is a matter of minor importance, since all agree in regarding 
the Ilfracombe limestones and associated slates as a definite central 
datum line, from whence to proceed either above or below. Mr. 
Hall observes that the North-Devon beds from Lynton to Pilton, 
though preserving a general dip to the south, are folded into many 
anticlinals, reducing their apparent thickness very considerably. 
Having got the North-Devon beds, which are really the key to 
the whole Devonian system, into something like order, it now 
becomes necessary to quit the county for a while in order to study 
the Old-Red Sandstone on the other side of the Bristol Channel. 
And here we realize the fact that there are two Old-Red Sandstones, 
the Lower of which is perfectly conformable with and passes down 
into the underlying Silurian, whilst the Upper passes conformably 
into the Carboniferous, of which system, in a certain sense, it may 
