68 



University bf California. 



[Vol. 3 



were found in much greater numbers and better preservation in 

 the underlying Trachyceras beds, so that there is no great faunal 

 distinction between the two horizons. 



" The Spiriferina beds. — These beds are made up of about 50 

 feet of limestone like that of the Atractites beds, but harder and 

 more silicious. They contain numerous fossils, especially brachio- 

 pods, which, however, cannot be got out without dissolving the 

 matrix. The most common fossil is a Spiriferina, or more prob- 

 ably, two species of this genus. Besides these are found: 



Rhynchonella conf. soli f aria, Hyatt. 



Terebratula sp. 



Trachyceras sp. 



Modiola sp. 



Gervillia sp. 



Pentacrinus sp. 



Oidaris sp. 



" Relations of the fauna of the Hosselkus Limestone. — The fauna 

 of the lower part of the Hosselkus limestone is undoubtedly that 

 of the zone of Tropites subbullatus and Trachyceras aon of the 

 Tyrolean Alps, that is of the lower Karnic. Several species are 

 identical in the two regions, and many others very closely related. 

 More than this, the stage of development of the ammonites is 

 identical, which is quite as good a proof of similarity in horizon 

 as identity of species." 



The saurian bones are found in all three divisions of the 

 Hosselkus limestone, but are best preserved and most common 

 in the Atractites and Trachyceras beds. 



Nearly all of the specimens are very firmly united with the 

 matrix in which they are embedded. They are generally much 

 like the rock in color and structure, so that in many cases it has 

 been almost impossible to separate them from it or even to define 

 their limits. In some specimens the difficulty in preparation 

 has been increased by the presence of irregular bodies of silicious 

 material replacing the limestone. Fortunately, many of the 

 bones are partly silicified, or a film of silicious material has 

 covered the walls of the canals and cavities, so that it has been 

 possible to bring out their form and structure quite distinctly 

 by the careful application of acids. 



