502 _ Notices of Memoirs—W. H. Hudleston— 
Swedish botanist Nathorst, speaking of the peculiar mixture of 
clay and stones known as the “‘ Head’ of Bovey Tracey,” called 
it Boulder-clay; and Mr. Pengelly likewise mentioned lately that 
another Scandinavian authority, Dr. Torell, when in company with ~ 
Mr. Ormerod as long ago as 1868, professed to have detected three 
moraines on Dartmoor in the neighbourhood of Chagford. That 
these were the results of an ice-cap, as that term is generally under- 
stood, I do not regard as probable; but bearing in mind the recorded 
facts, and also the frequency of such features as ‘“‘ terminal curvature,” 
we may well believe with Mr. Worth in the existence of something 
like a local snow-cap on the higher grounds. The peculiar nature 
of the cave-breccia, and the Arctic character of some of the cave- 
animals, also point in the direction of a colder climate. Not that 
this evidence is really required, except as a matter of corroboration. 
We may believe, then, in a glaciation so modified that its results 
require close search before they can be appreciated. 
Tse Extent anp Nature oF THE OretTAcEous Rooks. 
There are few problems in the physical history of the South-west 
of more interest than this. Speaking of the geology of the neigh- 
bourhood of Dawlish, Mr. Ussher says there can be little doubt that 
the Cretaceous highlands of Devon, such as the Haldons, are portions 
of a great plain of marine denudation, and he speaks of a time when 
that Cretaceous tableland abutted on the flanks of Dartmoor. He 
also refers to the presence of flints in the old and more modern 
gravels as evidence of the extension of Chalk débris. It is interest- 
ing to know that abundant fossil evidence of the former existence of 
Middle Chalk (the Upper Chalk of some writers) is found in the 
chert and flint beds which form the capping of Little Haldon; the 
Hchinodermata are especially characteristic. Mr. Ogilvie Hvans has 
called attention to this fact. 
As regards the former extension of the Chalk, I see no reason to 
doubt that the western part of what is now the Channel and the 
greater portion of Devonshire and Cornwall were submerged beneath 
the Chalk Sea. It seems to me that in no other way can you 
account for the quantity of flints on the western beaches and in the 
bottom of the Channel. But, irrespective of this corroborative 
evidence, one would expect the Chalk Sea to have extended in this 
direction. Then comes the question, Was there any western limit 
to the Chalk Sea, or did its waters mingle freely with the Atlantic 
Ocean during the period of extreme depression? At the epoch when 
the Upper Greensand, or basal sediment of the Chalk, was being 
laid down, Mr. Jukes-Browne, in his “Building of the British Isles,” 
represents the extreme western shore-line, plotted on the existing 
map of Devon as passing from the Ermemouth towards the Haldons; 
@.e. roughly parallel to the E.S.H. flank of Dartmoor. Now the 
distance from the Ermemouth to the present edge of the deep 
Atlantic basin is about two hundred miles, and that two hundred 
miles would represent the width of the land which intervened 
between the Upper Greensand Sea and the Atlantic Ocean at the 
