Another celebrated deposite of fossil fishes is that of the cupriferous slate surrounding the Hartz. Many of the fishes of this slate at Mansfeldt, Eiseleben, &c. have a distorted attitude, which has often been assigned to writhing in the agonies of death. The true origin of this condition, is the unequal contraction of the muscular fibres, which causes fish and other animals to become stiff, during a short interval between death and the flaccid state preceding decomposition. As these fossil fishes maintain the altitude of the rigid stage immediately succeeding death, it follows that they were buried before putrefaction had commenced, and apparently in the same bituminous mud, the influx of which had caused their destruction. The dissemination of Copper and Bitumen through the slate that contains so many perfect fishes around the Hartz, seems to offer two other causes, either of which may have produced their sudden deaths.[1]
From what has been said respecting the general history of fossil organic Remains, it appears that not only the relics of aquatic, but also those of terrestrial animals and plants, are found almost exclusively in strata that have been accumulated by the action of water. This circumstance is readily explained, when we consider that the bones of all dead creatures that may be left uncovered upon dry land, are in a few years entirely destroyed by various animals, and the decomposing influence of the atmosphere. If we
- ↑ Under the turbulent conditions of our planet, whilst stratification was in progress, the activity of volcanic agents, then frequent and intense, was probably attended also with atmospheric disturbances affecting both the air and water, and producing the same fatality among the then existing Tribes of fishes, that is now observed to result from sudden and violent changes in the electric condition of the atmosphere. M. Agassiz has observed that rapid changes in the degree of atmospheric pressure upon the water, affect the air within the swimming bladders of fishes, sometimes causing them to be distended to a fatal degree, and even to burst. Multitudes of dead fishes, that have thus perished during tempests, are often seen floating on the surface, and cast on the shores of the lakes of Switzerland.
