rALJSOKTOLOG*. 277 



Maypo in Chili), and D'Orbigny has described Ammonitei 

 and Gryphites from the Himalaya and the Indian plains of 

 Cutch, these remains being identical with those found in the 

 old Jurassic sea of Germany and France. 



The strata which are distinguished by definite kinds of pet- 

 rifactions, or by the fragments contained within them, ibrm 

 a geognostie horizon, by which the inquirer may guide his 

 eteps, and arrive at certain conclusions regarding the identity 

 or relative age of the formations, the periodic recurrence of 

 certain strata, their parallelism, or their total suppression. It 

 we classify the type of the sedimentary structures in the sim- 

 plest mode of generalization, we arrive at the following series 

 in proceeding from below upward : 



1. The so-called transition rocks, in the two divisions of 

 upper and lower graywacke (silurian and devonian systems), 

 the latter being formerly designated as old red sandstone. 



2. The lower trios* comprising mountain limestone, coal 

 measures, together with the lower new red sandstone (Todt- 

 liegende and Zechsteiu).f 



3. The upper trias, including variegated sandstonc,t mus- 

 chelkalk, and keuper. 



4. Jura limestone (lias and oolite). 



5. Green sandstone, the quader sanstcin, upper and lower 

 chalk, terminating the secondary formations, which begin with 

 limestone. 



G. Tertiary formations in three divisions, distinguished as 

 granular limestone, the lignites, and the sub-Apcunine gravei 

 of Italy. 



Then follow, in the alluvial beds, the colossal bones of the 

 mammalia of the primitive world, as the mastodon, dinothe- 



* Quenstedt, Ftitzgebirge Wurtembergs, 1843, s. 13. 



t Murchisoii makes two divisions of the bunter sandstone, the uppet 

 being the same as the trias of Alberti, while of the lower division, to 

 which the Vosges sandstone of Elie de Beaumont belongs the zec.t- 

 ttein and the todtliegende he forms his Permian system. He makes 

 the secondary formations commence with the upper trias, that is to say, 

 with the upper division of our (German) bunter sandstone, while the 

 Permian system, the carboniferous or mountain limestone, and the 

 devonian and silurian strata, constitute his paleozoic formations. Ac- 

 cording to these views, the chalk and Jura constitute the upper, and 

 the keuper, the muschelkalk, and the bunter sandstone the lower sec- 

 ondary formations, while the Permian system and the carboniferous 

 limestone are the upper, and the devonian and siluriau strata are the 

 lower palaeozoic formation. The fundamental principles of this general 

 classification are developed in the great work in which this indefatiga* 

 ble British geologist purposes to describe the geology of a large part of 

 Eastern Europe 



