398 THE CAMBRIAN. |boll.81. 



been accustomed to meet with ihem. The occurrence of a considerable number of 

 grypheae, the Gtyphea arcuata in a bed of blue clay in the mountains around the 

 Lake of Annecy in Savoy, served the author as a key to discover to what formation 

 the calcareous strata belonged, when their mineral characters would have indicated 

 a more ancient series. 1 



Be la Beche. — In 1832 an edition of the Geological Manual 2 of De la 

 Beche was published in Philadelphia. In the section upon the classifi- 

 cation of rocks we find the following remarks upon classifiation by 

 organic remains : 



To propose in the present state of geological science any classification of rocks 

 which should pretend to more than temporary utility would be to assume a more 

 intimate acquaintance with the earth's crust than we possess. Our knowledge of 

 this structure is far from extensive, and principally confined to certain portions of 

 Europe. Still, however, a mass of information has gradually been collected, partic- 

 ularly as respects this quarter of the world, tending to certain general and important 

 conclusions, among which the principal are, that rocks may be divided into two 

 great classes, the stratified and the unstratified ; that of the former some contain 

 organic remains and others do not ; and that the nonfossiliferous stratified rocks, 

 as a mass, occupy an inferior place to the fossiliferous 3 strata, also taken as a mass. 

 'The next important conclusion is, that among the stratified fossiliferous rocks there 

 is a certain order of superposition, apparently marked by peculiar general accu- 

 mulations of organic remains, though the mineral ogical character varies materially. 

 It has even been supposed that in the divisions termed formations there are found 

 certain species of shells, etc., characteristic of each. Of this supposition extended 

 observation can alone prove the truth; but it must not be supposed, as some now 

 do, that in any accumulation of ten or twenty beds, characterized by the presence 

 of distinct fossils in a given district, the organic remains will be found equally char- 

 acteristic of the same part of the series at remote distances. 



To suppose that all the formations into which it has been thought advisable to 

 divide European rocks can be detected by the same organic remains in various dis- 

 tant points of the globe is to assume that the vegetables and animals distributed 

 over the surface of the world were always the same at the same time, and that they 

 were ali destroyed at the same moment, to be replaced by a new creation, differing 

 specifically, if not generically, from that which immediately preceded it. From this 

 theory it would also be inferred that the whole surface of the world possessed an uni- 

 foim temperature at the same given epoch. 



It has been considered, but has not yet been sufficiently proved; that the lowest 

 rocks in which organic remains are fouud entombed show a general uniformity in 

 their organic contents at points on the surface considerably distant from each other, 

 and that this general uniformity gradually disappeared, until animal and vegetable 

 life became as different in different latitudes, and even under various meridians, as 

 it now is. How far this opinion may or may not be correct can only be seen when 

 geological facts shall have been sufficiently multiplied ; but it is one which demands 

 considerable attention, as the classification of fossiliferous rocks greatly depends upon 

 it. Should it eventually be found to a certain degree correct it would not be at va- 

 riance with the theory of a central heat, which having diminished permitted solar 

 heat and light gradually to acquire an influence on the earth's surface. 4 



Numerous other European works soon came into the hands of the 

 American geologists, among them the earlier editions of Bakewell, 



•Introduction to Geology, Robt. Bakewell, 1st American edition, New Haven, 1829, pp. 32, 33. 



'Geological Manual, Philadelphia, 1832. 



• The term fossiliferout is here confined to organic remains. 



♦Op. cit., pp.33,34. 



