416 
THE GEOLOGIST. 
the whole of our knowledge of the subject, as far as we have the power 
to do so, we shall be able to separate facts from fictions, and give a 
solid basis for further investigations in the future study of ornitholo- 
gical palaeontology. 
The first record of any allusion to petrified bird-remains is by 
Aleeetus Magnus, in 1495. His remarks evidently refer to those 
incrustations by calcareous springs which we should never now dream 
of associating with true fossils. Still, it is necessary for our purpose 
to record these, that the true may be separated from the doubtful ; 
while moreover these instances, if at all reliable, will serve the good 
purpose of illustrating the conditions under which true fossil ornithic 
relics may have been produced in the former geological ages of our 
earth. Such records are not to be cast aside as useless, for more 
reasons even than these. The following is the account given by this 
naturalist Bishop of Eatisbon in his ' Liber de Mineralibus,' pub- 
lished at Venice : — 
" In our time there was discovered in the Danish Sea, near the 
city of Lubeck, a big branch of a tree, whereon a nest of birds 
was found, and small woodpeckers in the nest, all converted into 
stone of a reddish colour ; the which cannot be otherwise explained 
than that the tree, at the time when the nest was in it, was rooted up 
by a storm, and the birds, drowned in the water, were afterwards, by 
the efi"ects of local circumstances, entirely converted into stone. 
There is also in Gothia a spring, respecting which tradition states that 
everything that is immersed in its water is converted into stone. 
The Emperor Frederick, wishing to ascertain the truth of this, 
ordered some sealed parchments to be put therein ; these having 
been kept there for a few days, the half of the skin, and the seals 
that is, the part submerged in the well, was changed into stone, the 
other part still remaining as it was. It is also positively stated by 
trustworthy people that the water-drops, which are dash-ed here and 
there by the force of the spring, are converted into as many stones as 
there are drops ; the water itself" however is not changed into stone, 
but continues to flow. AVe witness also the formation of crystals 
in the most elevated mountains perpetually covered with snow, 
which phenomenon cannot be ascribed to any other cause than to the 
virtue of the minerals which exist in those places. From all which 
we see that it is very difiicult to determine the place of generation 
of stones, the more so as they are formed not from a single but from 
many elements, and not under any special but under every climate; 
and what seems more marvellous, they are generated as well in the 
bodies of animals as in the clouds, and their formation in all of these 
places renders it scarcely possible to reduce them to the same com- 
mon matter. But as we cannot doubt that for a body of a compound 
nature there must be a generative cause, so it must be thence in- 
ferred that every kind has its peculiar place of generation, outside 
of which it decays and corrupts." 
" Aliquando namque tempore uostro in mari Danico juxta civitatem Lubi- 
