Notice of Dr. MantelVs Medals of Crealion. 113 



Strata. Prevailing fossils. Formations, 



Gypseous limestone, i Mammalia palcEOtheria, &c., birds, 



•'^ ' ( reptiles, nshes. 



Siliceous limestone, Shells. 



Lacustrine marls, Cyprides,phryganese, fresh- water shells. 



Monte Bolca limestone. Fishes. 

 Bone breccia, Mammalia and land shells. 



Sub-Himalaya sand- ? t:.! i. ^ , j b .-i 



1^ •' > Llepnant, mastodon, &c., reptiles. 



Tripoli, Infusoria. 



Richmond marl, Animalculse and infusoria. 



Semi-opal, Infusoria. 



Mountain meal. Infusoria. 



Guadaloupe limestone, Human skeletons, land-shells, coraJs, Human epoch. 



Bermuda limestone, Corals, shells, serpulee. 



Bermuda chalk, Comminuted corals, shells, &c. 



Bog iron ore. Infusoria. 



To this list may be added peat grounds, swamps and morasses 

 abounding with animalcules, both living and fossil. 



When it is understood that several miles in depth of the crust 

 of the earth are replete with the remains of organized beings, 

 and that numerous beds of great thickness are composed almost 

 entirely of them, we cannot wonder that a distinct work has 

 been written for these astonishing medals of the creation. The 

 vegetable world has also furnished its quota to form the solid 

 crust of the world. 



" Immense tracts of country are composed almost wholly of 

 the remains of plants in the state of anthracite coal, lignite, and 

 brown coal ] of submerged forests and peat mosses ; and of lay- 

 ers of trees and rocks transmuted into siliceous and calcareous 

 rock. Organic remains are found in almost every sedimentary 

 deposit of whatever kind ; but they abound much more in some 

 than in others, or are found more abundantly in particular parts 

 of the rocks, or are peculiar to certain rocks, some being peculiar 

 to the most ancient, others to the more modern, ' while some 

 genera range through the entire series of rocks, and also appear 

 as denizens of the existing lands and seas.' Hence they ac- 

 quire a high degree of interest, as they inform us of ' the physi- 

 cal condition of our planet in the most remote ages,' and ' they 

 are chronometers of the successive revolutions which the surface 

 of the earth has undergone.' By their aid, ' the relative age of 

 a formation or group of strata may be determined, as well as the 

 mode of its deposition and the agency by which it was effected ; 



Vol. xLViii, No. 1.— Oct.-Dec. 1844. 15 



