FUCHS MOLLtrSCA OF THE UPPEE TERTIARIES. 9 



On the Lay AS of Yesutitjs. By Professor Puchs. 

 [Proceed. Nat. Hist, and Med. Soc. Heidelberg, January 22, 1869.] 



The author states that the chemical composition of the Yesuvian lavas 

 is nearly the same from the oldest to the most recent. Soda is the 

 only very variable constituent ; it ranges from 1| to 5 per cent. This 

 variation is due to secondary chemical processes taking place before 

 the outpouring of the hiva. The three most essential mineral consti- 

 tuents are leuzite, augite, and magnetic iron. With these are asso- 

 ciated^ but often only in small quantities or in particular lavas, 

 olivine, mica, hornblende, garnet, sodalith, felspar (triclinic and 

 sanidine), nepheline, and apatite. Only a small portion of the leuzite 

 is in well- developed crystals, an indication that after its formation 

 it was partially altered by the high temperature of the surrounding 

 lava mass. Similar alterations appear to have been produced in a 

 great part of the constituent minerals of the lava. The lava, con- 

 taining both crystalline and amorphous mineral substances, must 

 have consisted at the time of its outflow of a fused mass in which 

 crystals and fragments of crystals swam. The author has repeated 

 and extended the investigations of Porchhammer and Hogers upon 

 the action of hot water under strong pressure upon the silicates of 

 which the lava is composed. This action is particularly energetic 

 Avhen the water contains carbonic, hydrosulphuric, sulphurous, or hy- 

 drochloric acid ; and it is to it that the author attributes the changes 

 produced in the chemical constitution of the lava. [W. S. D.] 



MoiLTJscA of the Upper Teetiaeies of the Yicentine. By 



Herr T. Pijchs. 



[Proceed. Imp. Acad. Yienna, July 23, 1868.] 



The whole number of species recorded by the author is 214 (among 

 which 71 are new), distributed as follows through the stratigraphical 

 subdivisions: — Castel' Gomberto strata 118, Laverda strata 12, 

 Sangonini strata 119. Of these 214 species, 128 are known to 

 occur in other localities, viz. 70 in the Inferior Eocene (Sables 

 inferieurs, Calcaire grossier. Sables moyens. Barton Clay, and their 

 equivalents), 91 in the Upper Eocene (Oligocene). Only 24 species 

 are common to the upper and inferior Yicentine Tertiaries, from 

 which last about 300 species are known, so that the limit between 

 the upper and inferior deposits is far more distinctly traced than it is, 

 for example, in the Hampshire basin, where, according to Prof, von 

 Koenen, 22 species, identical with those of the Barton Clay, are met 

 with amoug the 54 species of the Oligocene Pauna of Brockenhurst. 

 There is not one single species among the 300 just mentioned which 

 is, at present, known to occur exclusively in the Upper Eocenes, '^o 

 trace is found at Eonca of the comparatively far more recent spe- 

 cies erroneously ascribed to this locality, but in reality imbedded in 

 Castel' Gomberto strata or in the basaltic tuffs of Sangonini, while 

 Eonca offers many new forms associated with a surprising abun- 

 dance of beautiful Calcaire grossier forms. In consequence, the 



