660 MARINE UPPER TRIAS 



and slender. The incisors are separated, as in Phascolotlierium^ — a 

 marsupial characteristic. The structural form of the jaw, according td 

 Dr. Emmons's figure, shows some points of analogy with Simlacotherium^ 

 and some of difference. 



Dr. Emmons has named the fossil Dromatherhim sylvestre. He refers 

 the strata in which it was entombed to the Permian period, chiefly be- 

 cause they contain the remains of Thecodont Saurians ; but, as fossil 

 species of this family of reptiles have been met with in the Dpper Trias 

 of Wirtemberg, we cannot lay much stress on this argument. This fossil 

 may at least claim an antiquity equal to that of the Richmond coal-field, 

 in Virginia, described in the text, at p. 330. If so, the Dromatherium 

 would belong to the lower part of the Jurassic series, older than the 

 Stonesfield Slate ; and therefore it must be regarded as one of the most 

 ancient representatives of the mammalian class yet discovered. 



UPPER TRIAS OF THE EASTERN ALPS (p. 333). 



Eecognition of a Marine equivalent of the Upper Trias in the Au? Irian Alps- 

 True position of the St. Cassian and Hallstatt Beds — 800 new species of triassic 

 Mollusca and Eadiata — Links thus supplied for connecting the Palaeozoic and 

 Neozoic faunas. 



The true position in the series of certain Alpine rocks called "the St. 

 Cassian beds" has long been a subject of doubt and discussion, but the 

 researches of many eminent geologists, among others MM. Yon Buch, 

 E. de Beaumont, Murchison, and Sedgwick, and in Switzerland, MM. 

 Escher and Merian, and more lately in Austria, MM. Yon Hauer, Suess, 

 and Homes, have shown that these rocks are unquestionably referable 

 to the Keuper or Upper Trias. It has also been proved that the Hall- 

 statt beds on the northern flanks of the Austrian Alps correspond in age 

 with the St. Cassian beds on their southern declivity. By these discov- 

 eries we become acquainted, suddenly and unexpectedly, with a rich 

 marine fauna belonging to a period previously believed to be veiy barren 

 of organic remains, because in England, France, and Northern Germany, 

 the Upper Trias is chiefly represented by beds of fresh or brackish 

 water origin. Mr. Edward Suess, of Yienna, to whom we are indebted 

 for several memoirs on the rocks in question, has favored me with the 

 following summary of the order of succession of the Hallstatt beds in 

 the Austrian Alps, which I had an opportunity, when travelling in the 

 autumn of 1856, of verifying in company with Mr. Giimbel, of Munich. 



The uppermost strata first enumerated immediately, underlie the 

 Lower Lias of the Swabian Jura. This lias is represented near Yienna 

 by a brown limestone, containing Ammonites Bucklandi, A. Cony- 

 bearii, &c. 



