48 GEOLOGICAL MEMOIRS. 
per cent., according to Hertvig), must contain phosphoric acid. For 
no mauure has ever been put on these mountains which could have 
brought these salts of phosphoric acid; and these elevations, many 
of them very steep, have assuredly never been cultivated. This is 
also true of the neighbouring Siebengebirge. Without repeating the 
analysis of the trachyte of Drachenfels, we may confidently assert 
that it must contain phosphoric acid. Even where chemical analysis 
is no longer able to demonstrate the existence of a certain element m 
a rock, in consequence of the minuteness of its amount, the exami- 
nation of the plants growing on it, if the ground has not been 
manured, furnishes as valid a proof of the actual presence of an 
element as the analysis of the soil could do. 
[J. N.] 
LovEN on the Migrations of the Motxiuscous Fauna of 
SCANDINAVIA. 
[Zeitschrift fiir Malakozool. 1847, pp. 24-26. In L. and B.’s Jahrbuch, ~ 
1848, p. 256.] 
Tue molluscous fauna of Scandinavia consists of two elements, the 
German and the Arctic. The first attams its maximum in Bohus- 
Lehn and Southern Norway, the second in Finmark; im central 
Norway the two are mixed. During the ‘ Post-Tertiary period,’ 
only the high northern fauna existed in Scandinavia, a result which 
the author has deduced from the examination of the raised shell- 
beds on the west coast ever smce 1839. At a later period the fauna 
of the North Sea has gradually assumed a more southern character, 
the German as well as the Arctic forms have moved further north- 
wards, and some high northern species even died out in Scandinavia, 
whilst the German Ocean at present is inhabited by a pure Germanic 
fauna. Lovén thus distinguishes—(1) such species as are less nume- 
rous in high latitudes than m the North Sea, and in the Mediter- 
ranean are entirely wanting; (2) Hospites, including all the species, 
common to the Mediterranean; (3) Aborigines, or those chiefly de- 
veloped in high northern latitudes. An accurate comparison gives 
the followmg numbers of Conchylia (Gasteropoda Cochleata, Bra- 
chiopoda, Acephala). 
Proportion of the 
Number of species of Acephala to the 
Conchylia. Gasteropoda coch- 
leata, assumed = 100. 
——~ 
STE GRR. Spam pe, Pl 502 60 
pty ig 72 jy plea gaping rae ancien 413 91 
Sreland)! 2 /ReQU.. 22 339 83 
German Scandinavia............ 252 89 
Arctic Scandinavia ............ | 131 84 
Massachussetts ............2..... | 182 82 
Grepnibtid: > 2c) = gris | 11 49 
