300 RESEARCH IN CHINA. 
PO-SHAN. 
Spirifer bisulcatus Sowerby Productus granulosus Phillips 
Spirifer duplicicosta Phillips Bellerophon hiulcus Sowerby ? 
Spirifer (Martinia) glaber Martin Loxonema walciodorense De Koninck 
Productus semireticulatus Fleming Macrocheilus cf. intermedius De Koninck 
Productus punctatus Sowerby Phymatifer pugilis Phillips 
Productus humboldti d’Orbigny Naticopsis cf. globulina De Koninck 
Productus sublevis De Koninck? Orthoceras sp. 
Productus longis pinus Sowerby Crinoid stems. 
From Hei-shan, in the same general region, the following closely related 
fauna was obtained: 
Spirifer duplicicosta Phillips Productus semireticulatus Fleming 
Spirifer bisulcatus Sowerby Productus humboldti d’Orbigny 
Orthothetes crenistria Phillips Productus longis pinus Sowerby 
Productus giganteus Martin Macrocheilus cf. intermedius De Koninck 
I see no reason for doubting the evidence which tends to correlate the 
fauna from station 69 with that obtained by von Richthofen from Po-shan, 
although they have very few speciesincommon. Yet Frech calls this horizon 
Lower Carboniferous (Mountain limestone). My fauna presents but few 
facts of real evidence upon this point, and I will dismiss everything except 
the form which resembles Squamularia perplexa McChesney of the American 
Coal Measures. As the result of a great many observations of my own and 
some which are recorded in literature, Iam tentatively accepting the generali- 
zation that the early Carboniferous Reticulariz possess strong dental plates 
and a median septum, while the later ones (Squamularia) were without any 
sort of septal structures. More specifically, in our own section the Missis- 
sippian forms possess internal plates and the Pennsylvanian ones do not. 
Now, the Chinese fossils from station 69,sofar as can be ascertained, are with- 
out these internal structures. On this account especially, but also because 
the fauna has more or less of a Pennsylvanian facies and lacks anything 
distinctively Lower Carboniferous, I feel myself unable to correlate the Shan- 
tung collection with our Mississippian. In this difference from Doctor Frech 
in regard to the age of this horizon I suppose it is possible that he may be 
wrong and that the real age is Upper Carboniferous. In this connection the 
fact should be noticed that the diagnostic form Productus giganteus appears 
only in the lot collected at Hei-shan, and that it is represented only by a 
fragment. Another point which may not be without significance is that these 
faunas occur associated with coal beds. On the other hand, I very freely 
admit that my own determination may be wrong. 
But there is still a third possibility—that both determinations are right 
and that we are merely using terms in different senses. If I understand 
correctly, Frech would place this horizon in the Mountain limestone of 
European standards; but while the Mountain limestone is usually correlated 
with our Mississippian, it is possible that the upper beds of the Mountain 
limestone may overlap upon our Pennsylvanian. On the other hand, in 
applying the term “Upper Carboniferous” to this fauna I am using it not 
