330 



ORGANIC REMAINS. 



whole groups of these have been annihilated, and 

 have been replaced by others bearing widely different 

 characters ; and the changes of genera and species 

 are still more frequent Zoology and botany have 

 therefore become indispensable studies to the geolo- 

 gist. Before the importance of organic bodies in 

 discriminating the different formations was appreci- 

 ated, it was considered that a knowledge of minera- 

 logy was sufficient ; but the mineral character and 

 composition of which the strata of the earth's surface 

 are composed, very inadequately assist us in our in- 

 vestigations, for we find a similar succession of beds 

 of sandstone, clay, and limestone, irregularly re- 

 peated, not only in different, but also in the same 

 formations. Thus the same formation, which con- 

 stitutes the argillaceous deposits of the London clay in 

 England, exhibits at Paris the sand and freestone, of 

 what is termed the calcaire grossier ; whilst the 

 resemblance of their organic remains proves their 

 deposition to have been of the same epoch, notwith- 

 standing the difference in the character of their 

 mineral ingredients. 



" The secrets of nature, that are revealed to us 

 by the history of Fossil Organic Remains, form per- 

 haps the most striking results at which we arrive 

 from the study of geology. It must appear most in- 

 credible to those who have not minutely attended to 

 natural phenomena, that the microscopic examination 

 of a mass of rude and lifeless limestone, should often 

 disclose the curious fact, that large proportions of its 

 substance have once formed parts of living bodies. 

 It is surprising to consider, that the walls of our 

 houses are sometimes composed of little else than 

 comminuted shells, that were once the domicile oi' 

 other animals, at the bottom of ancient seas arid 

 lakes." 



It has been lately ascertained by Mr Ehrenberg, 

 that the rocks of homogeneous appearance, which are 

 not very hard, friable, even fissile, entirely formed 

 of silex, and which are known by the name of Tri- 

 poli, more or less solid, are entirely composed of the 

 exuviae, or rather of the perfectly ascertained skele- 

 tons of infusorial animals of the family Bacillarice, 

 and of the genera, Gomphonema, Synedra, Gallonella, 

 &c. Professor Jameson and Mr Nicol have examined 

 carefully, characteristic specimens of polishing slate, 

 and found in them numerous remains of lacustrine 

 infusoria, thus confirming the discovery of Ehrenberg, 

 in so far as applies to the Polier-slate. 



We may inform those who have not made geology 

 a study, that the word Formations is understood to 

 apply to certain groups of strata which have been 

 associated together for the sake of ready and simple 

 classification, and of avoiding the perplexity other- 

 wise arising from their numerous subordinate beds. 

 Hut for this comprehensive arrangement, it would be 

 difficult to distinguish, with sufficient precision, the 

 separate members of the secondary strata. As each 

 formation is in general made up of several members, 

 so also the latter are composed of an infinite number 

 of beds ; and those beds, again, of innumerable finer 

 lamina ; but the whole series being found to possess 

 some common character, some obvious relations, or 

 some general similarity in organic accompaniments, 

 or circumstances of position, they are appropriately 

 classed under one common denomination. 



It is in strata of the TRANSITION series that the first 

 remains of organized beings begin to be found, but 

 these are of the most simple construction in their 

 parts, especially in the inferior regions of this series. 

 But we find in them the remains of the four estab- 

 lished divisions of the animal kingdom ; viz. Verte- 

 brata, Mollusca, Articuluta, and Radiata ; thus prov- 

 ing these great divisions of animals to have been 

 coeval with the beginning of organic life on this 



globe, lint the highest degree of vertebral animals, 

 which have yet been found in the series, is fishes. 



In the SECONDARY strata, the only terrestrial 

 animals which have yet been ascertained, are some 

 small marsupial quadrupeds allied to the opossums ; 

 these are sparingly to be met with in the oolite for- 

 mation at Stonefield, near Oxford. Besides these, 

 Cuvier discovered two other small species in the 

 gypsum of the Tertiary formations of the Paris ba- 

 sin, thus proving that animals of this order were, con- 

 trary to what was supposed, in reality antecedent to 

 all other mammifera on our globe. 



The secondary strata present us with a series of 

 Saurian reptiles, principally of a gigantic size; many 

 of them marine ; others were amphibious, while a 

 third series were terrestrial, occupying savannas and 

 jungles. 



In the TERTIARY series we find that the fossil re- 

 mains, of both animals and vegetables, are much 

 more numerous, arid greatly more perfect in their 

 organization, and bring us down, by a natural transi- 

 tion, to those of our own times. Cuvier and Brong- 

 niart were the first who made us acquainted with that 

 important portion of the tertiary series, which form 

 the deposits above the chalk at Montmartre, near- 

 Paris. This at first was supposed to be peculiar to 

 that locality, but which later investigations have 

 proved to stretch extensively over the whole of our 

 globe, and presenting us with incontestable evidence, 

 of not less than four distinct periods of succession, 

 indicated by changes in the nature of the organic 

 remains imbedded in those strata. Every one of 

 these periods evinces an increasing provision for the 

 spread of animal existence, from the immense quanti- 

 ties of bones and shells found in the strata of these 

 epochs. 



Deshayes and Lyell have considered it necessary 

 to institute four divisions of the formations of the 

 tertiary series. The first of which they term the 

 EOCENE, signifying the dawn of the existing state of 

 animal creation. The London clay and calcaire 

 grossier of Paris are examples of the older tertiary 

 formations, an f contain but a very few species of 

 shells, of which we have living examples. The 

 second appellation is the MIOCENE, in which are in- 

 cluded formations of strata containing shells, the minor 

 proportion of which consists of recent species : for 

 example, the shells of Vienna, Turin, and Bourdeaux. 

 The third and fourth are the older and newer PLIO- 

 CENE, which, taken in conjunction, contain shells, 

 nearly the whole of which are to be met with in a 

 recent condition, but more abundantly in those of the 

 newer Pliocene ; in this division are the later forma- 

 tions of Sicily, Tuscany, and Ischia ; while the sub- 

 apennine marine formations, and English crag, are in- 

 cluded in the older Pliocene. These we have enu- 

 merated under their proper head. Alternating with 

 these four great marine formations, there intervenes 

 a fourfold series of strata, containing shells which 

 must have inhabited fresh water, associated with 

 numerous bones of terrestrial and aquatic mammalia. 

 The construction of these bones and form of the 

 shells clearly indicate, that their functions, in a liv- 

 ing state, must liave been exercised in a manner 

 similar to those now existing. 



Having -thus given a brief review of the progress 

 of discovery in Fossil Organic Remains, we shall now 

 discuss the subject in a systematic form, following 

 the descending scale of being, as in our other treatises. 



Many species of animals have existed on our globe 

 of which we have now living examples. Many con- 

 troversies have arisen, whether species have existed 

 since the first formation of animals, or whether they 

 were more simply formed at first, and have gradually 

 improved by reproduction, and assumed more enlarged 



