364 JOURNAL OF THE PLYMOUTH INSTITUTION. 
them two to three feet in diameter, there is a vast accumulation of 
vegetable matter in the immediately overlying clays. Between 
the stumps of the buried trees and in the lignite above them are 
many well-preserved cones of the Scotch and spruce firs. Professor 
Heer has identified amongst the plant remains those of the Scotch 
and Spruce firs, Yew, Yellow water-lily, Hornwort, Pondweed, 
Common sloe, Buckbean, White water-lily, Alder, Oak, and Birch. 
The insects, so far as they are known, including several species of 
Donacia, and also the freshwater shells, are, like the plants, of 
living species. Mr. Boyd Dawkins has identified a total of 26 
species of Mammals from the Forest, of which 16 are extinct and 
10 recent. On the authority of Professor Owen, at least four other 
species, all of existing forms, may be added to the list. The forest 
bed is overlaid by a great accumulation of deposits divisible into five 
distinct zones or horizons. 
With regard to the extent of the submergence during what may 
be called the inter-continental period, it will be remembered that 
Sir C. Lyell speaks of it as having converted the land north of the 
Thames and Bristol Channel, and that of Ireland, into an archi- 
pelago, thus allowing it to be inferred that the part of England 
south of the line specified was but little, if at all, affected by it; 
and this, as was intended, is positively conveyed to the eye by his 
Map representing the condition of the British Isles and part of the 
north-west of Kurope during the submergence.* Nevertheless, 
being not quite satisfied that this is a correct view of the case, I 
have elsewhere pointed out that there is conclusive evidence that 
the south of England participated to at least some extent in the 
submergence, and that there are facts which apparently require us 
to believe that the whole of Devonshire shared in the downward 
movement so far as to carry it at least 800 feet below its present 
level. + 
But, be this as it may, geology not only countenances the idea 
that Britain has been in a continental condition in what may here 
be called recent times, but it actually teaches that. within such 
times it has ¢wice been in that condition; that during some part of 
the interval it was submerged greatly below its present level; and 
* See ‘ Antiquity of Man,” Fourth edition, fig. 42, p. 325. 
¢ See “Trans. Devon Assoc.,” vol. vi. pp. 221-2. 1873. 
