B O L C A. 



645 



Bolca. ration of the learned, and the wonder of the igno- 

 1 k "' rant. It might he the work of a few hours, or at 

 most of a few days ; a truth which should so much 

 the more impress those naturalists who, on the phe- 

 nomena exhibited by the fossils of Verona, form 

 self-convincing arguments for the prodigious anti- 

 quity of the world." 



Several reasons are advanced by Testa on the pos- 

 sibility of the rise of Mount Bolca not being of very 

 ancient date ; but these perhaps were suggested by 

 his anxiety to make the antiquity of the world ex- 

 actly correspond with the common, though perhaps 

 erroneous, interpretation of scripture ; and in coun- 

 tries like his, so lately under the papal dominion, if 

 it was dangerous to think the reverse, it was still 

 more so to express it. " How many facts in natural 

 history," he exclaims, " have happened in ages not 

 remote from those in which we live, but which have 

 passed unnoticed and unremembered ! The celebra- 

 ted Lao-o d'Agnano, near Naples, did not exist to- 

 wards the middle of the 9th century ; but when was 

 it afterwards formed ? In what part of the territory 

 of Pozzuolo were those gold and silver mines situa- 

 ted, from which the bishops levied a tithe in 1135 ? 

 Under the reign of what prince were they abandon- 

 ed ? The Venetian chronicle of Sagornino, which is 

 not more ancient than the 11th century, speaks of 

 certain islands in the Lagunes of Venice, which no 

 longer exist. In what year did they disappear ? In 

 the 15th century, part of Giera was inundated by 

 the sea ; but we know nothing of its total desicca- 

 tion. Neither can we tell when the city of Gabi, 

 lately discovered in the Campagna di Roma, whose 

 succession of bishops terminates in the eighth cen- 

 tury, ceased to be inhabited ; for it is disclosed in 

 no history." He therefore concludes, that although 

 we may also search history in vain for the precise 

 epoch when the sea washed the foot of Mount Bolca, 

 and when the volcanoes of Lombardy still vomited 

 flames, we are not altogether void of traditions re- 

 specting it. Four thousand years ago, the sea may 

 have extended to the Vicentine mountains, and may 

 have formed so many islands of Berici and or The 

 Euganean hills. The names of extinct volcanoes be- 

 ing in the Italian language, induces Testa to suppose 

 that their craters have remained open subsequent to 

 the Christian aera ; for he cannot ascribe to simple 

 chance those such as Monteuuovo, Monterosso, Mon- 

 terugio, Moncenere, and the like. He cites exam- 

 ples of volcanic eruptions in the Vivarais, proved ,to 

 have existed in the 5th century, by the prayers offer- 

 ed up for their cessation. They have long since 

 been extinct ; though it is unknown when they cea- 

 sed to burn. " Mount Bolca is scattered over with 

 lava ; basaltic prisms crown its summit ; and even 

 the quarries containing its fishes are "covered with 

 a deep stratum of volcanic tufa." 



Theories not dissimilar from that of Testa are en- 

 tertained by other philosophers ; for all who have 

 studied the phenomena of this hill, incline to refer 

 them, in a great measure, to volcanic agency ; at the 

 same time judging the presence of the seaindispensible. 

 They maintain a principle, which we are inclined to 

 support, that the fishe3 extracted from the excava. 

 1 



tion3 of Bolca could be only a short time dead before 

 they were enclosed in the substance surrounding them ; 

 and as a necessary condition, that this substance 

 must have been in a very fine and pulverised state, 

 and either suspended in the water, where the fishes 

 swam, or subsiding from it. Thus, the water con- 

 taining them would be clear and fit for supporting 

 life, and the diffusion of the pulverised matter must 

 have been suddenly effected, whereby it arrested and 

 enclosed the fish in the masses formed by its deposit. 

 Certainly the deposit, excluding the access of water, 

 was speedily effected, otherwise the progress of pu- 

 trefaction, so powerfully promoted by humidity, 

 would have injured the figure of the animals, and the 

 various gases disengaged, would have deranged the 

 laminar structure of the flags it formed, by their frac- 

 ture or the formation of cavities. All this, the advo- 

 cates of the theory we allude to, explain by sup- 

 posing, that the explosion of a submarine volcano. 

 suddenly discharged a vast quantity of calcareous 

 matter into the sea above it. The fish within its 

 sphere were destroyed, the matter became pulverised, 

 and subsiding to the bottom, enclosed them in the 

 deposit. " The stone (where the fishes are enclosed* 

 is wholly calcareous, of a light colour, of a grain 

 dull, though fine, and entirely devoid of any crystal- 

 line or sparry appearance. Now, it is well known, 

 that limestone, whatever its original colour may have 

 been, becomes uniformly white or whitish, on being 

 calcined or burnt, more or less, to a lime; that after 

 this calcination, it immediately slacks or falls into a 

 powder, on being immersed in water ; and by agitation 

 is easily diffused in this element, from which, if left 

 in tranquillity, it soon subsides in a pulverulent state. 

 That this diffusion of lime in water, quickly deprives 

 of life such fish as happen to be within its reach ; 

 and, in fine, there is every reason to believe, that a 

 deposition of this nature possesses remarkably the 

 quality of quickly absorbing, even in water, oily and 

 other 6oft parts of animals; and when sufficiently 

 slacked, and thus impregnated with animal matter;, 

 without destroying the harder and firmer parts." 

 Applying this theory to the appearance of the flags 

 dug out of Bolca, it is supposed to receive a strong 

 confirmation from their structure. The deposition 

 of the lime gradually and successively concreting at 

 the bottom of the water, it is said, " may naturally 

 be expected to assume a flag like or laminar structure ; 

 the grain, too, of this new aggregate, should be 

 wholly without lustre, as well on account of its cal- 

 cination as of its formation, by subsidence from, not 

 in consequence of solution in, a liquid menstruum; in 

 which last case alone crystals are known to be form- 

 ed. This will farther easily account for the forma- 

 tion of the calcareous spar found within the promi- 

 nences occasioned by the joints of the vertebrae, and 

 the^ other grosser bones ; for these being fresh and 

 sound at the first arrangement of the stone, of course 

 excluded the subsiding matter ; but in process of 

 time, their hollows were filled, and by degrees as it de- 

 cayed, their Bubstance was replaced by a successive fil- 

 tration of water, holding calcareous matterin solution, 

 which deposited plate after plate its crystalline mat- 

 ter in these cavities." The fetid odour escaping by 



Bofca. 



