476 Reviews—A. J. Jukes-Browne—Building of British Isles. 
rocks upon whose stony flanks and platforms the softer Neozoic deposits 
were to be thrown down, these latter also to be hardened, raised up 
and sculptured in their turn. The Permian deposits may perhaps 
help to throw some light on the latter part of this revolutionary 
interval, since their fauna is linked with that of the preceding age, 
although their physical relations to the older rocks are of the most 
discordant character. 
We have now arrived at a time in geographical restoration when 
it is possible to speculate with some chance of being correct. Plate 
vy. introduces us to the geography of the Permian period. ‘The area 
is mostly land: an impounded water-space lies to the west of the 
Pennine chain, whilst on the east the Magnesian Limestone Sea is 
extended indefinitely across the central portion of the North Sea 
area, as though it might possibly still communicate with an ocean. 
The next plate represents the period of the Keuper, the continental 
phase still predominating in this area. A lake of curious shape 
extends from the Gulf of Normandy across the west centre of 
England until it is split by the Pennine mass into a north-eastern 
and a north-western area. This no doubt would be highly saline. 
Subsidiary basins, presumably of fresh water, occupy a southerly 
prolongation of the Minch and the Moray Firth. These two maps 
represent the great period of chemical precipitation in our area. 
By the time of the Lias and Inferior Oolite the general lowering 
of the land had enlarged this water-space, which now appears as 
an arm of the sea with marine connections across the Paris basin, 
but retaining in no small degree the shape of the old Triassic lake. 
There are even rivers, one of which flows in from the west at a 
point in the Bristol Channel between the coasts of Devon and Wales. 
Another river flows into an estuary opposite Cleveland, and a 
third debouches a long way outside the Moray Firth. These two 
rivers are supposed to drain the continent to the north-east; the 
embouchure in each case is within the area of what is now the 
North Sea, and consequently not accessible to close examination. 
Within the limits of the map there is a considerable preponderance 
of land. Premising that nearly the whole of the North Sea and the 
North Atlantic is represented as being land, the following blocks 
may be distinguished in addition: (1) the Highlands north of the 
Great Glen; (2) the bulk of Scotland with its continuations in the 
Pennine chain and towards the Isle of Man; (3) nearly the whole 
of Ireland; (4) Wales; (5) the Damnonian Peninsula; (6) the 
Palxozoics of Kent and East Anglia. It was these lands, and more 
especially the recently exposed Carboniferous, which provided the 
bulk of the Jurassic sediments. The view that the Jurassic clays 
were largely derived from the denudation of Coal-measure shales 
found an able exponent, some years ago, in Prof. Blake. It is — 
doubtful if much was derived from the hypothetical Hast Anglian 
land. 
Mr. Jukes-Browne considers that, allowing for oscillations at 
various times and in different places, the area continued to sink 
throughout the Jurassic period, and he does not hold the opinion, so 
