REPORT ON UPPER PALEOZOIC FOSSILS FROM CHINA. 299 
in the Ssi-ch’uan section with that which is next to the lowest, represented 
by lots 1, 2, 3,4, and 7. This fauna, containing as it does Schwagerina and 
Notothyris, is clearly Upper Carboniferous, and well up. 
The three overlying faunas are too scanty to determine their age very 
definitely. The greatest doubt surrounds the highest of these, that which 
was found in a gray limestone lying upon the Red Beds 7 miles (11.2 km.) 
south of Ta-ning-hién. From this horizon our collection affords only round 
crinoid stems, Dielasma ? cf. D. elongatum, Aviculipecten ? richthofeni Girty, 
and indeterminable fragments of pelecypods. 
The little pectinoid described as Aviculipecten ? richthofeni is of a type 
which is common in the Paleozoic, and doubtless in the Mesozoic as well. It 
has a somewhat related species in the Permian of Russia (Avicula kazanensis 
de Verneuil). The cardinal structures, and therefore the generic position, can 
not be ascertained from our material. The terebratuloid cited as Dielasma ? 
cf. D. elongatum has two large dental plates, but the structures of the dorsal 
valve, which are usually more difficult to ascertain, have not been satisfac- 
torily determined. I believe that it is not definitely known to what extent 
Mesozoic terebratuloids develop plates in the ventral valve, but it appears 
to be rather a peculiarity of Paleozoic shells. Upon this point Waagen says, 
speaking of Hemiptychina: “The genus is distinguished very characteristi- 
cally from the greater number of Paleozoic Terebratule by the absence of 
dental plates in the ventral valve. In this respect it approaches more closely 
to Mesozoic forms, in which dental plates are nearly always absent.’ [Mem. 
Geol. Surv. India, Paleeontologia Indica, Salt Range Fossils, vol. 1, p. 361.] 
It would appear from this that this type of structure is more common in the 
Paleozoic, though not entirely confined to faunas of that period. 
The evidence upon which the horizon in question is referred to the 
Paleozoic consists of the septiferous terebratuloid, the round crinoid stems, 
and the general Paleozoic complexion of the meager fauna. It is inconclusive 
and may not stand against any facts which strongly point to a Mesozoic age. 
For this reason my assignment to the Carboniferous is provisional merely, 
and should the necessity arise of changing to a younger period the readjust- 
ment would entail no serious conflict of evidence. 
The fauna from Y6n-yi-ssi, in Shan-si (lot 20), is very scanty and the 
only significant species is the crushed terebratuloid which, if correctly identi- 
fied as a Hemiptychina, would warrant placing this horizon also in the Upper 
Carboniferous. 
The collection from station 69, in Shan-tung, I refer to the Upper Car- 
boniferous with some reserve. From this point were obtained the following 
species: 
Chonetes sp. Squamularia cf. S. perpleca McChesney 
Marginifera sp. Cleiothyridina ? sp. 
From the same vicinity and at about the same horizon von Richthofen 
made a collection which Frech listed in the following terms: 
