REPORT ON UPPER PALEOZOIC FOSSILS FROM CHINA. 319 
The characters of the present shells, so far as known, are more like a group of 
species occurring in the American upper Devonian and lower Mississippian rocks 
than any which are known to me from the Upper Carboniferous. The peculiarities 
especially in mind are the low, broadly rounded or angular ribs and the absence 
of regular, fine, distinct, concentric crenulations; instead of the latter only faint 
incremental lines appear to be present. 
Locality and Horizon.—Pennsylvanian (Wu-shan limestone); Tung-kuan-k’6éu, 
East Ssi-ch’uan (station 17). Pensylvanian: near Ts’ai-kia-chuang, and near Yen- 
chuang, Shan-tung (stations 59 and 69). 
Productus ? sp. 
Plate 29, Figures 14, 15. 
This unusual form is represented by three specimens, each from a different 
locality. They show certain differences, which are regarded as being due to age 
and will be considered below. 
The smallest example has a width of 3 mm. and a length somewhat less. ‘The 
shape is semielliptical, perhaps contracting a little at the hinge. The cardinal angles 
were probably quadrate. ‘The shell is nearly flat and the only ornamentation con- 
sists of fine, sharp concentric wrinkles, of which there are eight. This specimen has 
the appearance of a very young Productus. ‘The concentric wrinkles in their sharp- 
ness and regularity somewhat suggest Leptena rhomboidalis, but the fine ribs of that 
species are not present. 
Another example has a width of 9 mm. and a length of about 7mm. ‘The 
cardinal angles are quadrate, the hinge-line straight, and the antero-lateral outline 
regularly rounded. ‘The convexity is low, the ears somewhat flattened, the beak 
small and depressed. The general shape is that of a young dorsal valve of Productus. 
The surface is marked by regular, fine, strong concentric wrinkles, 15 in number, 
increasing greatly in size with the dimensions of the shell. Toward the margin fine 
concentric strie can be made out. ‘The mesial area is, furthermore, marked by 5 or 
6 relatively coarse, somewhat obscure ribs, which are not so strong as the wrinkles 
with which they decussate. The more rostal portions of this specimen possess the 
same characters as the small example first considered. 
The third example is similar to that just described, except that it is a little 
larger and the wrinkles are a little coarser. 
This shell possesses the general appearance of Productus, but the sculpture, 
when considered closely, is unusual for that genus. Among our American Carbon- 
iferous species I recall nothing comparable to it, and of species of foreign description 
and occurrence but very few. It resembles to some extent P. plicatilis Sowerby, 
which Kayser identifies from Tshau-tién, but differs both from his and from David- 
son’s figures of that species. A certain amount of similarity can be traced also to P. 
undatus de France and to P. carringtonensis Davidson, as these species are recognized 
by Kayser and figured in his report. But it is not possible to identify my material 
with either. In point of being without radial ornamentation, except over a differen- 
tiated mesial portion, this form suggests Productus mesolobus as figured by Davidson 
from England and by Murchison, de Verneuil, and Keyserling from Russia. If a 
Productus at all it would perhaps belong to the group represented by P. mesolobus, 
though without question belonging to a distinct species. 
Although its characters are such as almost certainly to entitle the present form 
to recognition as a new species, no name has been proposed for it, both because it 
is imperfectly known and because of the uncertainty which surrounds its generic 
relations, 
