OF CORNWALL. 223 
appeared, they would have pointed out the feafon of the year when 
all thefe vegetables were interred, but I could find none. 
The place where I found thefe trees was three hundred yards 
below full-fea-mark ; the water is twelve feet deep upon them when 
the tide is in. Thefe feveral phenomena will enable us to draw 
from them fome interefting obfervations. 
Firft, That the body of thefe trees mull have flood at lead: twelve 
feet higher than at prefent; confequently there has been a fublidence 
on thefe fhores, and the ground has funk more than twelve feet. 
Secondly, Thefe foffil-trees diffidently confirm the tradition of 
thefe parts, that, where the fands are now firetching three miles in 
length, and a furlong (when the fpring-tide has retired to its full 
extent) in breadth, from the town of Penzance to St. Michael’s 
Mount, there was formerly a wood y . 
Thirdly, From the different levels of thefe vegetable remains, the 
body of the oak being many feet deeper than the undermoft roots 
of the fecond tree, it is plain that this fublidence could not have 
been equal in all its parts j the land funk in fome places more, in 
fome lels (as is ufually the cafe in all fubfidences, occafioned either 
by earthquakes, or by the fea’s exhaufting the Jirata , as Mr. Ray 
imagines, or by whatever other caufe 2 ), the fubfidence being in 
proportion to the depth of the cavities underneath, as well as accord- 
ing to the folidity and texture of the fhell above. 
Fourthly, This fubfidence of the earth had different tendencies 
in its feveral parts ; the firft tree feems to have preferved its per- 
pendicular fituation, and to have leant only a little forward towards 
the fouth, but the oak defcends obliquely into the fand with its 
top reclining to the eaft ; the motion therefore, which occafioned 
the fubfidence, was undulating. 
Fifthly, The ground which funk, appears to have been a fwarthy, 
marfhy plain of land, not much unlike the lower lands of Gulval 
and Ludgvan, parifhes adjoining, covered thick with trees of the 
oak, hazel, and willow, at leaf!, if there was not a greater variety. 
Sixthly, This fubfidence having happened fo many ages (proba- 
bly near a thoufand years) fince a , without being followed by any 
fucceeding convulfions or depreffions of the earth fince that time, 
(as far as we can learn) intimates to us, that where there are fuch 
fubfidences at the time of earthquakes, there is lefs danger of 
return, than where there are none ; the caverns below, from which 
the momentum proceeded, being filled and choaked up by the fall- 
ing in of the earth, and confequently fucceffive earthquakes are not 
to be dreaded ; but where there are no fubfidences, or very fmall 
r Leland Itin. vol. III. page 7. Carew, page 3. 3 See obfervations on the ScilJy Ifles, page ibid. 
Obfervations on the Scilly Ifles, page 92, &c. ut fupra. 
* See page 158 and 159 before. 
and 
