848 COSMOS 



the former beds of streams* In the geognostic character of 

 the soil of Tuscany, Steno recognized convulsions which must, 

 in his opinion, be ascribed to six great natural epochs (Sex 

 sunt distinctae Etruriae facies ex prsesenti facie Etruriee col- 

 lectEc). The sea had broken in at six successive periods, and, 

 after continuing to cover the interior of the land for a long 

 time, had retired within its ancient limits. All petrifactions 

 were not, however, according to his opinion, referable to the 

 sea ; and he distinguished between pelagic and fresh-water 

 formations. Scilla, in 1 670, gave drawings of the petrifac- 

 tions of Calabria and Malta ; and among the latter, our great 

 anatomist and zoologist, Johannes Miiller, has recognized the 

 oldest drawing of the teeth of the gigantic Hydrarchus of Al- 

 abama (the Zeuglodo7t cetoides of Owen), a mammal of the 

 great order of the Cetacea.t The crown of these teeth is 

 formed similarly to those of seals. 



Lister, as early as 1678, made the important assertion that 

 each kind of rock is characterized by its own fossils, and that 

 " the species of Murex, Tellina, and Trochus, which occur in 

 the stone quarries of Northamptonshire, are indeed similar to 

 those existing in the present seas, but yet, when more closely 

 examined, they are found to differ from them." They are, he 

 says, specifically different. $ Strictly conclusive proofs of the 

 truth of these grand conjectures could not, however, be ad- 

 vanced in the then imperfect condition of descrip^tive morphol- 

 ogy. We here indicate the early dawn and speedy extinction 

 of light prior to the noble palseontological researches of Cuvier 

 and Alexander Brongniart, which have given a new form to 

 the geognosy of sedimentary formations. § Lister, whose at- 



* Venturi, Essai sur les Ouvrages Physico-mathimatiques de Leonard 

 de Vinci, 1797, $ 5, No. 124. 



t Agostino Scilla, La vana Speculaxione disingannata dal Senso, Nap., 

 1670, tab. xii., fig. 1. Compare Job. Mtiller, Bericht uber die von Herm 

 Koch, in Alabama Gesammelten Fossilen Knochenreste seines Hydrachus 

 (the Basilosaurus of Harlan, 1835 ; the Zeuglodon of Owen, 1839 ; the 

 Squalodon of Grateloup, 1840; the Doradon of Gibbes, 1845), read in 

 the Royal Academy of Sciences at Berlin, April — June, 1847. These 

 valuable fossil remains of an ancient world, which were collected in 

 the State of Alabama (in Washington county, near Clarksville), have 

 become, by the munificence of our king, the property of the Zoological 

 Museum at Berhn since 1847. Besides the remains found in Alabama 

 and South Carolina, parts of the Hydrarchus have been found in Eu- 

 rope, at Leognan near Bordeaux, near Linz on the Danube, and, in 

 1670, in Malta. 



X Martin Lister, in the Philosophical Transactions, vol. vi., 1671, No. 

 Ixxvi., p. 2283. 



J See a luminous expositian of the earlier progress of palaeontologicaJ 



