1044 DE. TT-RTTR. ON THE FOSSIL FLOEA OF BOVET TEACEY. 
When a mass of timber and mud had been deposited in the bottom of the Bovey 
lake, some natural disturbance (whether owing to extensive landslips falling into the 
lake, or to the river undermining its banks) must have occasioned the contribution of 
a mass of quartzose sand, which thickly covers the under set of lignites, and which must 
at the time have helped largely to fill up the lake. Immediately above it lies a soft 
clay with numerous leaves of plants (the 26th bed), just as they were drifted together 
from the woods in the fall of the year. It seems, then, that this bed was formed in 
autumn, and that the plants it contains are due to the driftings of that season ; in 
further confirmation of which, is the frequent recurrence of the seed and ripe cones of 
Sequoia Couttsiae. Higher up follows the bed with the fern-rhizomes, among which 
occasionally can be recognized the pinnules of Pecopteris lignitum, which, somewhat 
higher up, amidst the branches of the Sequoia^ appear in great abundance, being here 
and there compacted together in dense masses. 
Above this bed come strata of clay and comparatively inconsiderable deposits of lignite, 
which last were all formed from the collection of wood and plants drifted to the spot. 
As this Lower Miocene formation is immediately succeeded by quartzose sand with 
"NVliite Clay, we have here a great hiatus. Either the Middle and Upper Miocene, as 
well as the Pleiocene periods, must have passed without the formation of deposits in 
this place, or the latter must have been removed during the Diluvial period. 
B. The White Clay. 
While the lignites and their alternating clays at Bovey present us with a vegetation 
which is subtropical, the plants of the White Clay exhibit a totally different character, 
and must have had their origin in a period altogether distinct. The collection of 
Mr. Pengelly contains four species from this formation — three of Salix and one of 
Betula ; and, what is the most remarkable, none of these appear to me. to differ from 
species now living. The little birch-leaves are not to be distinguished from those of 
Betula nana, Linn., nor the willow-leaves of one species from those of Salix dnerea, 
Linn. ; while those of a second species come very near Salix repens, Linn., and also 
resemble strongly those of Salix amhigua, Ehrh. So variable is the form of these 
leaves, that it is hard to fix the species with positive certainty. At all events these 
leaves prove to us that those white clays must be much more recent than the lignite 
deposit ; while the presence of Betula nana, Linn., which is in the highest degree 
remarkable, is conclusive for a diluvial climate, that is, a colder climate than Devon- 
shire has at the present day ; for this dwarf birch is an Arctic plant, which has no 
British habitat south of Scotland, and which occurs in Mid Europe only on mountams 
and subalpine peat-mosses. The evidence of the willow-leaves is to the same effect, 
indicating that at this period Bovey was a cold peat-moor. We may remark that Salix 
dnerea, Linn., is one of the most prevalent species of the diluvial travertine of 
Kannstatt. 
