268 C. SCHUCHERT— MORRISON AND TENDAGURU FORMATIONS 



ill the marine horizons, and when such are present they are isolated bones 

 that have been washed in from lower beds.^^ 



SECTION IN DETAIL 



The following detailed section is compiled in the main from Janensch 

 and relates to the immediate area of Tendagnru Hill: 



Tendaguru series. 



(1) Upper sandstones with Trigonia schwarzi. Thickness at least 5 me- 

 ters, but the top is not seen. 



The upper 4 meters or more consist of yellowish brown sandstone 

 that has silky bedding surfaces, with calcite crystals and bullet- 

 like concretions up to the size of a human head. When these 

 beds are calcareous they hold a rich marine fauna. 



Lower, coarse, whitish sandstone, about ^ meter thick. The 

 material is an arkose of sharp or rolled quartz, feldspar, and 

 granite pieces (up to several centimeters across), cemented by 

 carbonate of lime. The fauna in the main consists of thick- 

 shelled mollusks and numerous corals. 



The following described species occur in the T. schwarzi zone, 

 those in italics being guide fossils: 



Cephalopoda: 32 species, of which 19 are either new or can not 

 be identified. Belemnitcs pistilUformis, B. afii. subfusiformis, 

 Duvalia (D. elegantissima, new), Nautilus pscudoelegans, N. cf. 

 bouchardianus, N. cf. ncocomiensis, N. expletus, Phylloceras aff. 

 infundihulum, P. selum perlohata, P. deplanatum (new), Lyto- 

 ceras, Astieria (4 spp.), Holocostephanus, Holcodiscus (2 spp.), 

 Hoplites cf. neocomiensis, Crioceras aff. duvali, C. aff. meriani, 

 Hamulina cf. quenstedti, Bochianites. None of these species 

 occur below in the Trigonia smeei zone. 



Gastropoda : 17 species. Solarium, Pleurotomaria, Trochus hran- 

 cai, Tectus, Chrysostoma, Natica, Mesalia, Omphalia, Nerinea, 

 Nerinella, Cerithium, Ghenopus eurypterus. None are from 

 lower zones. 



Bivalves: Of species listed by Lange there are 83 in 37 genera. 

 From 20 to 50 per cent are related to Mediterranean forms. 

 Of these may be mentioned Gervillia dentata (also occurs be- 

 low), Camptonectes striatopunctatus, Syncylonema orhiculare, 

 Hinnites, Cyprina, Exogyra couloni, Modiola cequalis, Cucullcea 

 gahrielis, Trigonia schwarzi, T. smeei (rare here, from below), 

 T. transitoria, T. conocardiiformis, Sphcera cordiformis, Phola- 

 domya gigantea, Panopoea gurgitis, Protocardia schencTci (from 

 below), and Vola atava. 



Beachiopoda : Rhynchonella rauM, Zeilleria duUosa, and Kingena 

 transiens. 



Hennig : Op. cit., part iii, p. 164. 



