inner surface of the cranial bones. They consist of a ferruginous
compound, and, from their black colour, may be supposed to contain
manganese. Similar dendritic formations also occur, not unfrequently,
on laminated rocks, and are usually found in minute fissures and cracks.
At the meeting of the Lower Rhine Society at Bonn, on the 1st April,
1857, Prof. Meyer stated that he had noticed in the museum of
Poppelsdorf similar dendritic crystallizations on several fossil bones
of animals, and particularly on those of 'Ursus spelaeus', but still
more abundantly and beautifully displayed on the fossil bones and teeth
of 'Equus adamiticus', 'Elephas primigenius', etc., from the caves of
Bolve and Sundwig. Faint indications of similar 'dendrites' were
visible in a Roman skull from Siegburg; whilst other ancient skulls,
which had lain for centuries in the earth, presented no trace of them.*

[footnote] *'Verh. des Naturhist'. Vereins in Bonn, xiv.
1857. I am indebted to H. v. Meyer for the following
remarks on this subject:--

'The incipient formation of dendritic deposits, which were formerly
regarded as a sign of a truly fossil condition, is interesting. It has
even been supposed that in diluvial deposits the presence of
'dendrites' might be regarded as affording a certain mark of distinction
between bones mixed with the diluvium at a somewhat later period and
the true diluvial relics, to which alone it was supposed that these
deposits were confined. But I have long been convinced that neither
can the absence of 'dendrites' be regarded as indicative of recent age,
nor their presence as sufficient to establish the great antiquity of
the objects upon which they occur. I have myself noticed upon paper,
which could scarcely be more than a year old, dendritic deposits, which
could not be distinguished from those on fossil bones. Thus I possess a