FAUNA OF THE PROVINCE OF THE MEDITERRANEAN. 1i1 
confusion into any stratigraphical or genetic classification. We have not yet 
been able to find any such case! 
Examples of mixed faunas such as have been quoted above are not so exten- 
sively mixed as has been claimed. The Hierlatz and Adneth limestones are, 
for example, mixtures only of the faunas of the beds above the Angulatus bed; 
the examples given of so-called psiloceran forms as occurring in them are due 
to mistakes in identification, since these forms are species or young of species of 
Arnioceras or Agassiceras, and the species cited as belonging to the Middle and 
Upper Lias are either radical forms or else morphological equivalents, like all 
the so-called anachronic forms which we have yet studied. A paper by W. B. 
Clarke is very instructive in this connection, since he found in the Rheetic a true 
Arcestes, showing conclusively how favorable this region must have been for the 
preservation of ancient forms. He also was able to make out and describe the 
Planorbis and Angulatus horizons, with a full list of species already described by 
Wiihner and others, and, above this, the Hierlatz horizon. 
The facts appear also to accord perfectly with the theory of autochthonous 
faunas. Ifthe Northeastern Alps were the seat of origin for the major portion of 
the radical forms of Arietides, we should naturally expect to find in this province 
the geological and zovlogical relations which are shown in Table VI.; namely, 
a clear definition of the lower formations and faunas throughout the Planorbis 
and Angulatus horizons, and an extraordinary number of radical species and 
their immediate allies, these also having in the sutures a more ancient or triassic 
aspect than in Central Europe. An analdainic fauna made up of modified forms 
arising by migration from other faunas would necessarily be shown either in the 
admixture of forms above these horizons in case the sediments were similar and 
continuous, or else in the non-appearance of new radical or progressive forms if 
the sediments were more varied and more distinctly separable, as in England 
and in the basin of the Rhone. 
While the Mediterranean province was an analdainic fauna so far as the Arie- 
tide were concerned during the deposition of the upper beds of the Lower Lias, 
subsequent to the deposition of the Angulatus beds, this was by no means the 
case with other groups, such as the Lytoceratide. On the contrary, as has been 
already announced by Neumayr, this province was the autochthonous home of 
this family, and Neumayr’s opinion is strongly sustained by the remarkable series 
of species described from the Northeastern Alps by Geyer, Hauer, and others, and 
an especially fine series by Herbich from Siebenburgen. . The Lytoceratide are 
by no means absent from the faunas of the Lower Lias in Central Europe, though 
generally quoted as being found in the Middle and Upper Lias. Thus Amu. 
Driani, Dumortier, and Amm. Salisburgense and Amm. ailus of the same author, are 
apparently members of this family, found in the Oxynotus bed of the basin of the 
* Barrande, with all his knowledge and close study of the fossil Cephalopoda, has not been able to prove 
a single example. Those he has given are readily explained as morphological equivalents, and we have 
found by the investigation of Bohemian specimens that the Nautili of the present time are entirely different 
from paleozoic forms. As soon as the nepionic and nealogic stages are studied and compared, they are 
found to be distinct. This is also true of his Gon. (our Celeceras) prematurum. 
* Geol. Verhiilt. d. Geg. nordw. vy. Achen-See. 
