29 
Hyatt. 
have come from Italy by the way of the valley of the Rhone. The 
faunas of the Italian rocks have been referred to the Mediterranean 
province by Neumaj^er and several other authors, and the mixed 
character of the faunas above the Angulatus beds has been noticed, 
especially by Geyer. There seems to be every reason for closely 
associating them throughout the Lower Lias with those of the 
Northeastern Alps, and all the specimens we have seen are either 
peculiar forms or have a Mediterranean facies. 
It has seemed, therefore, unlikely, that any connection existed 
during the time of the Lower Lias between the Central European 
and the Mediterranean province to the west of the Northeastern 
Alps basin. This opinion, established on purely palseozoological 
grounds, receives confirmation from two different geological con- 
siderations. The Planorbis bed is either absent or very slightly and 
insufficiently presented in Italy according to all the works we have 
seen, and this is also the case along the shores of Provence. It is 
present in deposits reaching from the neighborhood of Toulon to 
Nice, according to M. Dieulefait, but does not contain any Am- 
monitinse. This author 1 draws a boundary line between the rocks 
of the Lowest Lias in southern Provence or department of the Var 
and those of the valley of the Durance and department of the Basses 
Alpes. His researches show very clearly by means of the geology 
and palaeontology, that no connections probably existed between 
these closely approximated areas during the deposition of the Pla- 
norbis and Angulatus beds, and farther, that the upper beds of the 
Lower Lias are entirely wanting in the Mediterranean part of 
Provence, while they are well developed in the valley of the Dur- 
ance. 
This sustains the views here advanced that the migrations began 
during the time of deposition of the Planorbis or possibly some- 
what earlier beds and flowed out from the Northeastern Alps in two 
directions. One took the route to the south and west into the Ital- 
ian region, and, perhaps, farther westward into Spain, though of 
this last we have no proofs to offer. The other stream of migrants 
spread more directly westward into Bohemia and South Germany 
first, then into the Cote d’Or, but reached the Rhone and all faunas 
south of the autochthonous zone later. In the same way as re- 
gards England and the faunas north of this zone, they all, as we 
Ann. des Sci. Geol., vol. i, pi. v. 
