The presence of the sea, however; on the Vero nese territory, is not indispensible to the existence of the fishes of Bolca. A volcano on the surface of the earth may have been the sole agent. Sonic philosophers affirm, that all volcanoes have a commu nication with the sea by subterraneous caverns. Mount Vesuvius vomited quantities of water in 1538, and in later times : and Etna, in 1755, cast up salt water, mixed with stones and sand. But we have still more decisive proof, how essential volcanic agency might be in producing the fishes of Bolca, from learn ing that vast quantities of a species of small fishes have been discharged from the burning craters of mountains in South America ; sometimes in such ex traordinary numbers, that their putrefying bodies threatened to create a pestilence in the land. Vol canic eruptions in the vicinity of the sea, or of lakes, are commonly fatal to vast multitudes of fishes ; on which account, those which issued from the Peruvian mountains might have perished before being absorbed by the craters. Pliny, in describing the fafal catas trophe wherein his uncle perished, remarks, that the sea suddenly ebbed during the eruptions of Vesuvius, -and many animals remained dry on the sand : and centuries afterwards, a similar phenomenon allowed the inhabitants of the neighbourhood to collect the fishes lying dead on the shore. During the rise of new islands from the sea of the Greek Archipelago, dead fishes continued to be thrown up during a whole month on the sand : and an instance, still more no ted, was seen in 174.2, at the port of 'Vera Cruz in Mexico. A sudden agitation of the sea on the Igth of October, threw down part of the wall of the city, ' and threatened the vessels in the harbour with de struction. Next day incredible quantities of fishes covered the beach, lying in hears on each other; and consist:; many species altogether unknown to the fishermen : nor were they confined to the vicinity of the port, as the same appeared at the distance of leagues from it. The heaps were so great, that, to avert the danger of putrefaction infecting the atmosphere, all the slaves of the place, and the crews of the royal gallies, were employed in burying them in the places where they lay. The like phenomenon was renewed in the island of Sumatra, in the year 1755, when an amazing multitude and variety of fishes, some dead, others dying, were found on the shore. We arc, therefore, entitled to maintain, that fishes may be vomited from the crater of a volcano ; and to con clude that volcanic eruptions arc sometimes singular ly destructive of those in the surrounding seas. Dif ferent theories are entertained respecting the cause of their death. Some naturalists conceive that a mephi tic vapbur is suddenly diffused throughout the water, which immediately becomes fatal animals with in its sphere ; that they are involved in showers of volcanic ashes, which then become the deposit of their bodies, and the source, as in the case before us, of their future preservation. The fishes of Bolca have unquestionably perished by sudden death, as is demonstrated by the half digested food in the sto machs of some of the most voracious. Those who oppose the deposit being formed at the bottom of the sea, maintain, that the fishes, once exposed on a dry Shore, might easily be covered and invested by show ers of ashes, which, while forming a crust around them, would aid the absorption and evaporation of the water ; and that their gradual accession is particu larly favourable to preserving the figure of the ani mals enclosed, from the superineumbent' weight not being sufficient to crush them. As the strata of Boles, along with fishes, contain the leaves of trees, terrestrial. plants, &tilts, and flowers, and even some winged ani mals, this hill could not be at the bottom of the sea when the deposit was formed, because the lightness of leaves always buoys them up on the water. Volcanic showers also are heavy enough to break them off the trees, and are e.vcn capable of killing birds ; and that psculiar odour emitted by the flags is improperly re ferred to an animal principle, for it should rather be called bitumenous. The ashes discharged in forming the new islands of the Archipelago were mixed with Much bitumen, which served as a gluten to bind them together, consolidate them, and involve the substan ces which they covered. Those from an eruption of Vesuvius in 1737, spread over the gulf of Ve nice, and at Zanrichelli diffusd a similar odour, which assuredly, say the partizans of this doctrine, could not be imparted by putrefying fishes. " Vol &Mc showers," in the words of Domenico Testa, " having fallen on Bolca, destroyed and burned to gether, the fishes of the sea, the birds of the air, the trees; and plants of the earth. Thus did an eruption form that celebrated cemetery of fishes, which for two centuries has equally been the admi-.
ration of the learned, and the wonder of the igno ' 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 Lago 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 Enganean 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 sera ; for he cannot ascribe to simple chance those such as Montenuovo, Monterosso, Mon terugio, Moncenere, and the like. He cites exam ples of volcanic eruptions in the Vivarais, proied Ito 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 sea indispensible. They maintain a principle, which we are inclined to support, that the fishes extracted from the excava.
;drills 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 advd 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 and subsiding to the bottom, enchised '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 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 soft parts of animals; and when sufficientlir 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 expectedt'o•assume a flag like or lathinar 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, riot• in consequence of solution in, a liquid menstruum; in which last case alone crystals are 'mown to be form ed. This will farther easily account- for fortna 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 olthe stone,'of course excluded the subsiding matter • but in process"of time, their hollows were filled, and by degrees as it cayed, their substance was replaced by a successive fil tration of water, holding calcareous matteein'solution, which deposited plate. after plate its crystalline mat ter in these cavities." '.The fetid odour-escaping- by friction on every part of the stone, is considered a strong presumption also, that its whole substance has absorbed a great proportion of animal matter.