326 CALIFORNIA ACADEMY OF SCIENCES. [Proc. 3D Ser. 



The Geography of the Trias. 



The Triassic system took its name from the peculiar three- 

 fold development in the Germanic basin, in which at the 

 base are beds of sandstone, in the middle are massive and 

 shaly limestones, and at the top, clay shales and thin beds 

 of quartzite. This basin was an interior sea, wholly cut 

 off from the outside world during the greater part of its 

 existence; but its sediments are so accessible to students of 

 European stratigraphy that its local names have been used 

 to designate subdivisions of the Trias all over the world. 

 And ever since the extension of local names became cus- 

 tomary, geologists have been sorely puzzled to know how 

 to identify the pelagic equivalents of Buntsandstone, Musch- 

 elkalk, and Keuper, since those inland deposits seldom 

 contain any of the open-sea species. 



Instead of being the type of the Trias, the Germanic 

 basin sediments are the exception, and the type is to be 

 sought in strata that were laid down along the borders of 

 open seas. These have long been known in the limestones 

 and shales of the Alps, Himalayas, Salt Range, Siberia, 

 and western America, but the nomenclature has always been 

 obscured by local names. There is therefore an urgent 

 need for some uniform system of nomenclature by which 

 Triassic open-sea sediments may be correlated directly with 

 each other, without reference to the old and unrecognizable 

 divisions. 



The Vienna geologists. Dr. E. von Mojsisovics, Dr. W. 

 Waagen, and Dr. C. Diener, have attempted to give the 

 desired classification, in a paper entitled " Entwurf einer 

 Gliederung der pelagischen Sedimente des Trias-Systems" 

 (27). The authors divide the Triassic pelagic deposits into 

 four series, Scythic, Dinaric, Tirolic, and Bajuvaric; and 

 these again into stages and substages, and further into- 

 zones, the latter having usually only a local value. The 

 correlation table published in the present paper is adapted 

 from that of these authors, as is also the nomenclature of 

 the subdivisions. 



