Hyatt.] 
26 
l May 16, 
Oxynoticeras made its appearance on about the same level in all 
the faunas so far as can be judged by the evidences ; but the other 
species of this series and of the sub-series of Oxyn. Greerioughi 
show that it probably arose in the Cote D’Or and was distributed 
from that centre. 
The basins of the Northeastern Alps in the Mediterranean prov- 
ince and of South Germany and the Cote D’Or in Central Europe 
may therefore be considered as marking out a zone during the time 
of the Lower Lias, running east and west, which was especially fa- 
vorable for the evolution of the new forms and series which are in- 
cluded in the family of the Arietidse. I have accordingly named 
these basins the Zone of Autochthones, or zone of autochthonous 
faunas in the Lower Lias. 
The fauna of the Lower Lias in the basin of the Northeastern Alps 
is, however, not in the zone of autochthones after the deposition of 
the Angulatus bed. This zone, before the deposition of the Lower 
Bucklandi bed, had become narrowed in its easterly extension and 
was confined to the faunas of South Germany and the Cote D’Or. 
This is shown not only by the diminution in the number of forms 
of each series represented in the strata of the basin of the North- 
eastern Alps, but also by the concentration of the beds and the 
mixed character of the faunas above the Angulatus bed. The best 
general summary of the facts in regard to the faunas of the different 
beds of the Lower Lias has been given by Wahner 1 in his “ He- 
teropischen Differenzirung des Alpinen Lias.” This author, whose 
keen discrimination of species I have had constant occasion to ad- 
mire, has been able to distinguish all the Oppelian beds from the 
Planorbis to the Angulatus bed in the Northeastern Alps, but he 
has entirely failed, as have others, in defining the beds above this, 
so as to make a parallel series with those of Central Europe. Stur , 2 
Gumbel , 3 Geyer , 4 Herbich , 5 and others may be quoted in favor of 
the opinion that the faunas of the strata above the Angulatus bed 
are mixed, and that the beds cannot be separated as in the prov- 
ince of Central Europe. They have failed in obtaining any direct 
evidence of subdivisions after careful investigations, and their ci- 
tations of the minute work of others show the same result. Some 
of these authors go so far as to claim that the faunas above the 
Angulatus beds in the Northeastern Alps not only contain species 
1 Verh. d. k. k. geol. Reichsan., 1888, p. 168. 2 Geol. d. Steivmark, p. 433. 
8 Geogn. Beschrieb. d. bayeris. Alpen, p. 428. 4 See op. cit. 6 See op. cit. 
