432 KEUPER AND MUSCHELKALK FORMATIONS. [Ch. XXII. 



nized, it was found convenient to have a common name for all the 

 strata intermediate in position between the Lias and Coal ; and the 

 term " PoiMlitic " was proposed by Messrs. Conybeare and Buck- 

 land,* from iroiniXog, poikilos, variegated, some of the most charac- 

 teristic strata of this group having been called variegated by Werner, 

 from their exhibiting spots and streaks of light-blue, green, and buff 

 color, in a red base. 



• A single term, thus comprehending both Upper and Lower New 

 Ked, or the Triassic and Permian groups of modern classification, 

 may still be useful in describing districts where we have to speak of 

 masses of red sandstone and shale, referable, in part, to both these 

 eras, but which, in the absence of fossils, it is impossible to divide. 



Trias or Upper New Red Sandstone Group. — As the group of 

 strata now to be considered is more fully developed in Germany than 

 in England or France, it will be well to consider in the first place the 

 manner in which it presents itself in that country. It has been called 

 tKe Trias by German writers, or the Triple Group, because it is sepa- 

 rable into three distinct formations, called the " Keuper," the 

 " Muschelkalk," and the " Bunter-sandstein." 



Nomenclature of Trias. 



German, French. English. 



Keuper, - Marnes irisees, - - i Saliferous and gypseous 



r ' ' ( shales and sandstone 



, T , „ ,, ( Muschelkalk, ou calcaire ) .. • -r, -, -, 



Muschelkalk, - - ] „__««__ ' [ wanting in England. 



1 coquillier, 



Bunter-sandstein, - Ores bigarre, - - \ Sa * dst ° ne and q^rtzose 



° ' { conglomerate. 



Upper Trias, or Keuper. — It has been already stated, p. 419, that 

 near the base of the Lower Lias are certain zones of strata, distin- 

 guished by the abundance of peculiar species of ammonite, in one of 

 which A. BucMandi, and in another still lower A. Planorbis abound. 

 In Northwestern Germany, as in England, beneath these ammonitifer- 

 ous zones, there occurs a remarkable bone breccia, a marine forma- 

 tion, the shells of which are distinct from those of the Lias. It is 

 filled with the remains of fishes and reptiles, almost all the genera of 

 which, and some even of the species, agree with those of the subja- 

 cent Trias. This breccia has accordingly been considered by Profes- 

 sor Quenstedt and other German geologists of high authority, as the 

 newest or uppermost part of the Trias. Professor Plieninger found 

 in it, in 1847, the molar tooth of a small Triassic Mammifer, called 

 by him Microlestes antiquus. He inferred its true nature from its 

 double fangs, and from the form and number of the protuberances or 

 cusps on the flat crown ; and considering it as predaceous, probably 

 insectivorous, he called it Microlestes, from [HKpog, little, and Xyarrjc, 



* Buckland, Bridgew. Treat., vol. ii. p. 38. 



