642 



B O L C A. 



Bolca. that of swine-stone. This odour, the Abbe Fortis, 

 """ V ' in treating of petrified shells found not far from Bolca, 

 supposes to proceed from animal putrefaction. On 

 splitting the flags asunder, the remains of petrified 

 fishes appear of a dark brown colour, and are co 

 quently very conspicuous on the light ground of the 

 stone. They lie flat between the lamina; j their contour 

 and component parts being little, if at all, distorted 

 from their natural shape and dimensions ; but some- 

 times there is an enlargement or defect, arising either 

 from the changes undergone in passing from an animal 

 to a fossil state, or by the stone apparently having been 

 affected by motion after they were inclosed within it. 

 Their whole form is completely defined, and the 

 harder parts, such as the head, fins, spine, and other 

 bones, are still more evident. The dark brown sub- 

 stance composing the fish remains quite distinct, and 

 projects from the laminae of the stone, in proportion 

 to the size of each part in its natural state, and it 

 may be separated from the stone. It is hard, brittle, 

 and rather glossy, excepting some of the larger bones, 

 such as the joints of the vertebrae, which, though 

 presenting the same external appearance, exhibit ca- 

 vities filled with beautiful crystals. The different 

 colour of the slate, or flag, inclosing the fishes, has 

 been ascribed by naturalists to the chemical effects 

 of their bodies on the stone, which is not improbable, 

 on reflecting that it could not be originally in an in- 

 durated state. Fossil fish are found in various parts 

 of the world, and high above the present level of the 

 sea, but no where in the same abundance as in the 

 quarries of Mount Bolca ; and the fishes of this hill 

 are further distinguished from the impressions usually 

 seen in argillaceous schistus, as well as from the pe- 

 trifactions of shells found in limestone strata. In the 

 latter nothing more than the simple impression of 

 the fish remains, and the external shape of the shell is 

 alone preserved, whereas, in the productions of Bol- 

 ca, the form and size of the animals are not only ad- 

 mirably exhibited, but there even seems to be the re- 

 sidue of animal matter, in that substance which we 

 have said may be detached from the stone. Inspec- 

 tion determines it to be of a different nature from 

 that of the inclosing stone, and, so far as could be 

 judged without analysis, those naturalists who have 

 bestowed most attention on the subject, conclude it 

 to be animal remains ; and that it is in a condition 

 similar to the flesh of mummies ; from which cir- 



cumstance Volta denominates the state of these fishes 

 natural embalming. 



Most of the fishes of Bolca are such as now inha- 

 bit the European seas, but there are some species 

 peculiar to the rivers of India and America exclu- 

 sively, while there are many belonging to tlie fresh 

 water streams of our own and neighbouring coun- 

 tries. It is asserted by observers, that petrified 

 American fishes are found in no other part of Eu- 

 rope, notwithstanding there are numerous impres- 

 sions of European ones in France, Switzerland, Ger- 

 many, Britain, and elsewhere. 



Of many hundred specimens dug from the quar- 

 ries of Bolca, the species amount to 94' ; the rarity 

 er abundance of which is extremely diversified, as 

 well as the size of each. Some have been found 

 three feet in length ; and, in 1789, ihepegasus nutans, 



a small fish, was dug out of Lastrara, which, from 

 its minuteness, almost escaped notice. Thus the 

 natural agent affecting their transition from the ani- 

 mal to the fossil state, has equally operated on the 

 bodies of alL A young shark, now preserved in a 

 cabinet, merits particular observation. It is only 25 

 inches in length, wanting a small portion of the tail, 

 and four in breadth ; and more perfect than any of 

 the same genus found in Bolca, though the remains 

 of sharks of much larger size have been procured. 

 The ravenous nature of the animal is disclosed by 

 the contents of its stomach, which exhibits a quanti- 

 ty of sea crabs ; but it is wonderful to remark, that 

 these are in a half digested start-. Considering the 

 voracity of such fishes, it is evident that death must 

 very soon have followed the capture of the prev. 

 Certain appearances denote incipient putrefaction, 

 which plainly proves, that the commencement r>f the 

 transition to the fossil state must have speedily ar- 

 rested its progress. The sudden change which en- 

 sued is further corroborated by the skeletons of two 

 fishes imprinted on the same stone ; one of which has 

 seized the head of the other, and seems in the act of 

 swallowing it. This is esteemed one of the most 

 singular productions afforded by Bolca. The genus 

 chaitodon has more frequently been described than 

 others, either from readily occurring, or from being 

 better adapted for preservation. Scheuchzer long 

 ago observed, that the chcetodon pinnatus, a fisk 

 commonly inhabiting the Arabian and Indian seas,' 

 was dug out of Bolca ; and more modern European 

 naturalists, on comparing the fossil with the real ani- 

 mal, ascertain, that, in the transition undergone, some 

 parts have either enlarged or become defective. Th. 

 chcutodon meso/euctis, lately transmitted from Japan, 

 and which still lives in the seas of Africa also, is 

 found entire in Bolca. This fish, which is neither 

 mentioned by Artedi nor Linnaeus in its living state, 

 was first discovered by Forskhal on the shores of 

 Arabia ; and Bloch afterwards received it from the 

 island of Japan. Gmelin, however, in his edition of 

 the Systema Naturm, probably being influenced by 

 the remoteness of these two regions from each other, 

 has formed two species, which seem to constitute 

 only one. The fossil extracted from the quar- 

 ries of Bolca corresponds with both. Among the 

 finest specimens procured, is the chwtodon argtis, 

 bearing a minute and perfect resemblance to that 

 caught in the rivers of India, or in stagnant lakes. 

 where it feeds on insects, and animal substances sup 

 plied to it. The chxtodon argus is conjectured to 

 pass through extensive seas, for it has been described 

 as inhabiting places many degrees asunder. So fai 

 as hitherto ascertained, the chtetodon arcuatus hat 

 never been seen in tiie European seas, yet it is dug 

 out of Bolca. Marcgrave enumerates it among the 

 fishes of Brazil, and Artedi classes it with those in- 

 habiting India. Two specimens from the hill, which 

 are still preserved, first proved it to have anciently 

 existed in Europe. There is a fish of uncommon 

 structure, called the sea bat by the older ichthyolo 

 gists, and thence c/itttodon vespcrtilio by the mo- 

 derns, which very few have described. Willoughby 

 speaks of it, but it was unknown to Linmcus, and 

 seems to be found solely in the seas surrounding 



Bole*. 



