j SUBTERRANEOUS FORESTS. , 231 
H Pfopf,rtio„ 
as the -worknien proceeded to a greater 
. lastly, the petrifactions, known by the name 
Itttve been found in chalk pits, in different 
the kingdom ; they are usually cylindrical, or 
SUp’ sometimes contain a hollow nucleus. They 
*' 1 ti»^y to constitute a species of nautilus, and very 
y Occur in the coarser kinds of marble. 
Ij StJBTEnBANEOUS FORESTS. 
I? I7O8, a breach made by the Thames, at an 
high tide, inundated the marshes of Dagen- 
J|‘Kf'^j,^^‘''vei-ing, in Essex. Such was the impetuous 
n!' ''’^’or, that a large passage or channel was torn 
ill feet in width, and in some parts twenty 
V K ■. ihis way, a great number of trees, which 
\v- there many ages before, were exposed to 
exception, that of a large oak, having 
1 ?** ill j ^ P'>ft of its bark, and some of its heads and 
1 >e , perfect state, these trees bore a greater reseni- 
'0 a . . 1. .. j • .1 
S V ^ uitui lu Lui_y uiiici UC.-.L.1UJHW11 \jL w\jKi\A, 
A® hlack and hard, and their fibres extremely 
ony doubt was entertained of their having 
^'0 spot where they now lay ; and they were so 
D^*'=tig(, ’ ^' 8 t in many places they afforded steps to tire 
y were imbedded in a black oozy soil, on 
ol which tliey lay prostrate, with a covering of 
'’long the channel torn up by the water, vast 
.■silil,. Ot thg .r .1 . 
tllKiP^Ss 
stumps of these subterraneous trees, re- 
Ijk’ soj^' posture in which they grew, were to be 
O'^liiug ® their roots running down, and others 
spreading about in the earth, as is observed 
"fltat they were the ruins, not of the 
• 
... f a later age, has been inferred from the 
de * shells, which lies across the highway, 
,/^®trt near Stiflbrd Bridge, leading to South 
' lted*^nf |’®’"pendicular depth of twenty feet be- 
Miio^'^ ffiM shelfs, and at the distance of nearly two 
W bottom of the valley, runs a brook 
^Itij^Ptes itself into tlie Thames at Purfleet. This 
to ebb and flow witli the T hanies j and. 
