MACKIE FOSSIL FETJITS FEOM THE CHALK. 
3 
have been hollowed out to their shells and then Jilled in. Whether 
these fruits and other vegetable remains in the chalk be so rare as 
has been thought, 1 somewhat doubt. I have myself collected frag- 
ments of fossils from the lower chalk of Dover and of Maidstone, 
which I believe, since I have seen these specimens, to have been fruits 
like them — and some few of these I think are still in the Folkestone 
collection — but in all cases the specimens seem to have suffered much 
decomposition from long-continued immersion before they were com- 
pletely imbedded. 
Here then, at the very outset, we are met with a difficulty which 
must be surmounted before we can compare with any usefulness these 
relics of the arborescent vegetation of the far-distant Cretaceous age 
with the fruits of any living class of trees. There are some in the 
botanical collection in Kew Gardens which present many points of 
similarity, but we should by no means be inclined to say of identity. 
The greatest mischief to fossil botany has arisen from the fact that 
many, if not most of our fossil species, have been named and described 
by men who were not botanists ; and as so little is known of the vege- 
table remains preserved in the English chalk, we refrain from giving, 
and should hesitate long before we assigned, botanical characters to 
any new form from that formation, especially when so vaguely pre- 
served as those before us. 
We would however suggest that the film-like character of the 
ochreous envelopes of these fossils may be thus explained : — Sup- 
posing the fruits to have been solid nuts contained in a husk like the 
nipadites, — and in the cases of the British Museum there are fine spe- 
cimens of nipadites from the middle eocene of Brussels, well riddled 
with teredines ; the same is well known to be the case with the 
nipadites and other nut-like fruits of the London clay, — while the 
nuts were in the earliest stage of decay, a film of sulphuret of iron 
was deposited in the empty interspace between the nut and its outer 
husk, forming thus, when solidified, a thin metallic paper-like pellicle 
or case, having on its interior surface the impression of the exterior 
surface of the kernel, and on its exterior surface that of the interior 
of the husk. The fruit and husk might both then wholly decay away, 
and leave this metallic shell to be imbedded and filled in by the na- 
tural deposition of the cretaceous mud. Thus it will be desirable in 
searching for further specimens to look carefully for, and to preserve 
any fragments of real wood or black charcoal, however small, which 
may be attached to the inside or outside of the ochreous film, as in 
these fragments we might get some traces of structure to aid us. 
