FORMATIONS AND FOSSILS OF SOUTH MANCHURIA 41 



species appears very much like Stromato'pora (?) inanchuriensis 

 Yabe and Sugiyama, but differs from it in having comparatively 

 more regular concentric and vertical layers while S.{f)manchuriensis 

 presents a general vermicular aspect. 



Formation and locality. — Middle Ordovician, Ssuyen formation: 

 At the base of the lower fossil horizon of the black banded lime- 

 stone, near Pen-hsi-hu, Mu-hsin-tai, and on the Fu-chin-kou ridge, 

 Liao-tung, Manchuria. 



Cotypes.—US.'^M. Nos. 83625 to 83627. 



ECHINODERMATA 

 Genus CARABOCRINUS Billings, 1853-1856 



CARABOCRINUS species undetermined 



Plate 33, Figure 13 



Louderback's collection from central China contains one large, 

 strongly marked plate of a crinoid, which bears the characteristic 

 markings of the genus Cardbocrinus. Even though this specimen 

 (U.S.N.M. No. 83628) is only a single plate, I have illustrated it, 

 as, so far as I know, this is the first discovery of this crinoid in the 

 Orient. 



Formation and locality. — Upper Ordovician: Near Chao-tien, 

 Szechwan, China. 



BRACHIOPODA 



Genus ORTHIS Dalman, 1828 

 ORTHIS CHINENSIS, new species 



Plate 33, Figubes 1-8 



Description. — Shell subcircular to subquadrate in outline; length 

 of hinge line about equal to width of shell; cardinal angles obtuse 

 or subrectangular. Pedicle valve strongly convex, swollen; beak 

 rather high, incurved ; hinge area rather large, triangular. Brachial 

 valve slightly convex, with a weak median depression widening an- 

 teriorly; beak small, inconspicuous, not raised; hinge area narrow, 

 nearly at right angles to valve. Interior of brachial valve unknown. 



The external surface of both valves is ornamented with a variable 

 number of rounded, rather strong ribs, which increase in number 

 from about the middle of the margin by both regular and occasional 

 interpolation of one or two smaller ribs between each pair of the 

 larger ones. Ribs curve back slightly on both sides toward cardinal 

 angles. Ribs and interspaces crossed by some irregular concentric 

 striae and usually marked with a number of longitudinal striae. 



The dimensions of a nearly complete, medium-sized specimen (pi. 

 33, figs. 4, 8) are: Height of pedicle valve, 16 mm; height of brachial 



