25 
period of the deposition of the beds of clay and lignite which now 
occupy its bottom. Mr. Pengelly’s researches have been made 
chiefly at the pit near Bovey Tracey, from which the lignite is 
extracted for oeconomic purposes. The section obtained in the south 
wall of this pit shows upwards of seventy beds of clay, sand, and 
lignite, measuring 125 feet in thickness. Of sand there are only 
four beds, three near the surface, and one of great thickness near 
the middle of the deposit, dividing the formation into an upper and 
lower series. In sections further to the east the upper sand-beds 
disaj^pear, and at the same time the great middle sand-bed thins 
off from about eleven feet to ten inches, furnishing clear indications 
that the source of the materials of the deposit must have been the 
granitic region of Dartmoor, lying to the north-west. The estimated 
thickness of the deposit near Bovey Tracey is at least 218 feet, but 
the total amount of material deposited is probably far greater. 
About seventy fathoms east of the pit there is a fault, beyond 
which a totally distinct set of beds is found: these consist of clays 
and sands, with only a single thin stratum of lignite, and Mr. 
Pengelly regards them as constituting the upper part of the 
formation, of which the lignitiferous portion near Bovey Tracey 
has been deprived by denudation. The lignite beds, which in the 
Bovey Tracey section have a total thickness of 44 feet, are composed 
of the remains of plants, carried down into the lake from the high 
grounds surrounding it. The greater portion of these have been 
converted into mere lignite, in which no structure can be detected, 
but in some both of the lignite and clay beds recognisable portions 
of plants are met with, sometimes in great abundance. The plants 
found indicate that the vegetation must have flourished under, at 
least, a sub-tropical climate. They include species of laurel, 
cinnamons, fig-trees, and similar plants, and also a climbing palm, 
allied to those common in the Brazilian forests. Beyond the region 
on which these plants grew, and probably on the Dartmoor range, 
there must have been at the same time a vast forest of coniferous 
trees, belonging to the genus Sequoia , the only living species of 
which are to be found in California. One of these is the tree 
commonly known as the Wellingtonia gigantea , and celebrated for 
the enormous size to which it attains; its relatives in the vicinity 
of Bovey Tracey were also of large dimensions, the remains of 
trunks measuring at least six feet in diameter having been met 
with. The fragments of this tree, described as Sequoia Couttsice , in 
honour of Miss Burdett Coutts, at whose expense Mr. Pengelly’s 
