FOSSIL INFUSORIA. 191 



of south latitude all the surface ice carried along by currents, and the sides of every berg, and 

 the base of the great Victoria barrier itself — a perpendicular wall of ice, from one to two 

 hundred feet above the sea-level— were tinged brown from this cause, as if the waters were 

 charged with oxide of iron. The majority of these plants consist of simple vegetable cells, 

 enclosed in indestructible silex (as other Algce are in carbonate of lime) ; and it is obvious tliat 

 the death of such multitudes must form sedimentary deposits of immense extent. 



" The universal existence of such an invisible vegetation as that of the Antarctic ocean, is u 

 truly wonderful fact, and the more so, from its being unaccompanied by plants of a high ordei'. 

 This ocean swarms with mollusca, and entomostracous crustaceans, small whales, and porpoises ; 

 and the sea with penguins and seals, and the air with birds : the animal kingdom is everywhere 

 present, the larger creatures preying on the smaller, and these again on those more minute ; all 

 living nature seems to be carnivorous. This microscopic vegetation is the sole nutrition of the 

 herbivorous animals ; and it may likewise serve to purify the atmosphere, and thus execute in 

 the antarctic latitudes tlie office of the trees and grasses of the temperate regions, and the broad 

 foliage of the palms of the tropics." ' 



Dr. Hooker also observes, that the siliceous cases of the same kind of Diatoraaccie now 

 living in the waters of the South Polar Ocean, have contributed in past ages to the formation 

 of European strata ; for the tripoli and the phonolite stones of the Ehine contain the siliceous 

 shields of identical species. Such are the comments of one of our most eminent botanists on 

 the phenomena under review. The reader will probably ask, — What, then, are the essential 

 characters which separate the animal from the vegetable kingdom ? To this question it is 

 impossible to give a satisfactory reply: perhaps the only distinction that will be generally 

 admitted by zoologists and botanists is the following : — animals require organic substances for their 

 support ; vegetables derive their sustenance from inorganic matter. 



The facts thus cursorily reviewed throw much doubt on many of M. Ehrenberg's statements 

 as to the identity of species of animalcules now living, with those whose remains occur in the 

 eocene, and in the secondai7 strata. The so-called Xanthidia of the chalk, are certainly 

 altogether distinct from the recent diatomte to which the name was first applied ; the chalk 

 organisms are probably the gemmules of sponges or other zoophytes.^ 



Infusorial earths may therefore be composed either of microscopic vegetable or animal remains, 

 or of both. The brackish and fresh- water deposits I have examined are siliceous and almost wholly 

 diatomaceous : the marine calcareous strata composed of microscopic organisms, consist chiefly of 

 various kinds of foraminifera, a large proportion belonging to the polythalamia, or chambered 

 shells. I am not certain as to the animal or vegetable nature of some of the beautiful siliceous disks 

 {Coscinodisci, Arachnoidisci, Actinocycliis, ^-c.) so abundant in the Eichmond, Barbadoes, and Ber- 

 muda infusorial earths, and which occur in so splendid a state in the Guano deposits of Ichaboe. 



With the corrections which the above remarks will enable the reader to make, I would refer 

 to the account of Fossil Infusoria in the Medals of Creation, and Wonders of Geology .^ 



XV. The Mosasaurus, or Fossil Reptile of Maestricht. (Plate LXX.) The occasional 

 discovery of bones and teeth of an unknown animal in the limestone of St. Peter's Mountain, near 

 Maestricht, and the innumerable shells, corals, teeth of fishes, claws of crabs, echini, and other 



1 From Dr. Hooker's account of the botany of the South Polar regions in Sir J. Ross's Voyages of Discovery. 



2 It would be convenient to distinguish these fossils by another name, and thus avoid the perpetuation of the error ; 

 I would propose that of Spiniferites, in allusion to the numerous spines with which all the species are beset. 



3 See also " Thoughts on Animalcules." 



