142 The American Geologist. September, 1903. 
upper horizon of the Middle and the lower zone of the Upper 
Devonic, and their occurrence in numerous species is a feature 
that marks and distinguishes the three abpve named regions. 
The relationship of the Altai is also greater with the Mugad- 
zhar Mts. than with the Urals. 
In the Middle Devonic of the Altai-West-Siberia region 
occur Favosites 7, Coenites 1, Striatopora 1, Roemeria 1, Al- 
veolites 3, Heliolites 1, Aulopora 2, Syringopora 1, Am plexus 
2, Calophyllum 1, Cyathopacdium i,Cyathophyllum 5, Meso- 
phyllum 2, Spotigophyllitm 2, Phillipsastraea 3, Cystiphyllum 
1, Calceola sandalina. 
MIXED TYPE. 
North Siberia. — The corals of this region are of species 
that have "immense vertical and horizontal distribution, as 
Favosites cristatus, Alveolites sub orbicularis, Aulopora ser- 
pens, Cyathophyllum cacspitosum and C. hexagonum." Baron 
Toll, after a review of the entire fauna of North Siberia, con- 
cluded it to be a mixture of Ural and American types and of 
the Stringocephalus horizon. "It is worthy of remark that the 
deposits of the Stringocephalus horizon, which in West Siberia 
do not show any decided affinity with the same deposits of 
America, have, farther to the east in the region explored by 
Toll, forms in common to both these areas." 
SUMMARY. 
West European type. — The Middle and Upper Devonic 
coral faunas of this subprovince are marked by an abundance 
of Cyathophyllum, massive and branching Favosites, Cysti- 
phyllum, Acervularia, Spongophyllum, Endophyllum, Meso- 
phyllum, Phillipsastraea, Alveolites, Campophyllum- and Stro- 
matopora, a less abundance of Pachypora, Striatopora, Hel- 
iolites, Aulopora, and the presence of Amplexus, Calophyllum, 
Coclophyllum, Metriophyllum, Hadrophyllum, Microcyclus. 
Pachyphyllum, Calceola, Chactctes, Michelinia, Plagiopora, 
Roemeria and Syringopora. 
Central Russian type. — The Middle and Upper Devonic 
coral faunas of this subprovince are marked by a paucity of 
species. Favosites is represented by a few forms, while the 
genera Coenites, Striatopora, Phillipsastraea, Acervularia and 
Endophyllum are absent. The .faunas consist essentially of 
Syringoporidac and Cyathophyllidae. 
