PISHES IN THE HAR.TZ. 109 



Another celebrated deposite of fossil fishes is that of the 

 cupriferous slate surrounding the Hartz. Many of the fishes 

 of this slate at Mansfeldt, Eiselebon, &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 Bitu- 

 men 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 death.* 



From what has been said respecting the general history 

 of fossil organic Ucmains, 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 accu- 

 mulated 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 



• UikIpi' tlie turbulent conditions of our plnnct, wliiist stratification was 

 in progress, tiie activity of volcanic agents, then frequent and intense, was 

 probably att.enckd also witli aimospheric disturbances affecting- botli tlie air 

 and water, and producing the sanne fatality among- the then existing Tribes 

 of fishes, that is now observed to result from sudden and violent changes ia 

 the electric condition of the atmosphere. M. Agassiz has observed that ra- 

 pid changes in the degree of atmospheric pressure upon the water, affect 

 the air witliin the swimming bladders of fishes, sometimes causing t'lem to 

 be distended to a fatal degree, and even to burst. MultiUides of dead fisiies, 

 that have thus perished during tempests, are often seen floating on the suJ"- 

 lace, and cast on the shores of the lakes of Switzerland. 



