§ 15. STRATA COMPOSED OF ORGANIC REMAINS. 889 



Strata. Prevailing Organic Remains. Formations. 



Purbeck and Sussex ) 



marble > Fresh- water shells, and Crustacea . Wealden 



Wealden limestone. J C ^ es > and other fresh-water j ___ 



| shells, Crustacea, reptiles, fishes . j 



Tilgate grit (some beds) j Bonesof reptUes, fishe^ freah-water J _ 



Faringdon gravel . . Sponges, corals, echini, and shells [ *™ e ^~ 



Jasper and chert. . . Shells 



Greensand Fibrous zoophytes 



Chalk Poly thalamia and other animalcules^ e a " 



J ( ceous 



(Corals, shells, ammonites, belem-^ 



Maestricht limestone J nit es, and other cephalopoda- [ __ 



I reptiles J — 



Hippurite limestone . Shells, principally hippurites . . __ 



Hard chalk (some beds) Echini and belemnites .... 



( Sponges, & other fibrous zoophytes ;^ 

 Flints | Infusoria, &c 



(Echini, shells, corals, crinoidea . 



Limestone Freshwater shells Tertiary 



Nummulite rock . . Nummulites 



Septana Nautili, turritellae, and other shells 



Calcaire grossier . . . Shells and corals 



Gypseous limestone . | Bones of mammalia, (Pal<zotheria,\ 



\ &c.) birds, reptiles, fishes . . . j 



Siliceous limestone . . Shells — 



Lacustrine marl . . (Cyprides, phryganeae, fresh-water) 



\ shells J 



Monte Bolca limestone Fishes — 



Bone-breccia .... Mammalia, and land-shells ... — 



Sub-Himalaya sand- f Bones of elephants, mastodons,) 



stone j Reptiles, &c j 



Tripoli Infusoria — 



Semiopal Infusoria — 



Richmond earth . . Infusoria — 



Guadaloupe limestone | Hum an bones, land-shells, and \ Human 



I corals j epoch 



Bermuda limestone . Corals, shells, serpulae, infusoria . — 



Bermuda chalk . . . Comminuted corals, shells, La. . — 



Bog-iron ochre . . . Infusoria — 



