CORRELATION OF TENDAGURU SERIES 279 



Jurassic to the Neocomian, with the T. smeei beds a straddle formation from 

 Kimmeridgiaii to Purbeclvian ; and I make no objection. . . . 



"Tlie Tendaguru series, it seems to me, began about tlie time of the Sun 

 dance, and, witli perliaps several invisible stratigraphical gaps — non-sequences 

 we call tliem here — bridged the break between Sundance and Morrison, finish- 

 ing off in Neocomian times." 



n a 



later letter (February G, 1917) Buckman adds: 



"I do not see why the upper dinosaur clay is placed in the Neocomian. Why 

 should not this be associated with the T. smeei zone, and the break between 

 Jurassic and Cretaceous be placed above it? What is the reason for not taking 

 such an obvious course?" 



Conclusions by Schudiert. — From the preceding synopsis of the work 

 of the German paleontologists and of Buckman, it is seen that all are 

 agreed that the Trigonia scktvarzi marine zone, a sandstone of about 16 

 feet in thickness, is of Neocomian (lower to middle) or Lower Cretaceous 

 time. Some of the forms, however, are indicative of as high a stage as 

 tlie Barremian, and this means that this fauna is a mixed assemblage, of 

 which some species, in the Mediterranean countries, lived only during a 

 limited part of the time, either during the middle or the lower part of the 

 Lower Cretaceous. 



Beneath the Trigonia schwarzi zone lies the upper dinosaur horizon, 

 of 130 feet thickness, composed of sandy shales and sandstones. This is 

 referred by the Cermans to the base of the Lower Cretaceous, mainly 

 because it appears to them that the Tendaguru is a continuous series of 

 deposits, and further because the next older marine T. smeei zone is of 

 the Upper Jurassic (Kimmeridge and Tithonian). 



We are told that there is no striking difference between the saurians of 

 the upper and middle dinosaur zones, while there is a total dissimilarity 

 in the lower one. In other words, the same genera and in some cases 

 even the same species of dinosaurs, it would appear, lived in Jurassic and 

 Lower Cretaceous times, while the marine faunas changed considerably 

 in the same time. 



The dinosaur distribution is as follows : 



Gigantosaurus africanus Upper dinosaur zone. 



Gigantosaurus rohustus Upper dinosaur zone. 



Brachiosaurus hrancai Upper and middle dinosaur zones. 



Brachiosaurus fraasi Upper and middle dinosaur zones. 



nicraosaurus sattleri Upper dinosaur zone. 



IHcrwosaurus hansemanni Middle dinosaur zone. 



Kentrosau7'US irthiopicus Upper and middle dinosaur zones. 



Omosaurus (?) Upper and middle dinosaur zones. 



Polacanthus (?) Upper dinosaur zone. 



