1 86 RESEARCH IN CHINA. 



the palpebral lobes of 1 7 mm. ; the glabella is 8 mm. in width, with a length, including 

 the occipital ring, of 14 mm. 



This species differs from Ptychaspis cacus [plate 17, figs. 10, n] in the globose, 

 overhanging frontal lobe of the glabella, and the form of the frontal rim, features 

 that also separate it from P. cadmus [plate 16, fig. 19] and P. calchas [plate 16, fig. 

 13]. From P. acamus [plate 16, fig. 18] it differs in the form of the frontal lobe of 

 the glabella and the transverse lobe back of it. The globose glabella resembles 

 that of P. granulosa Owen [1852, p. 575], except that it is more globose and over- 

 hangs the frontal border. Ptychaspis granulosa has a different form from the other 

 Chinese species. 



Formation and Locality. Upper Cambrian: (f 38) Crystalline limestone near 

 the base of the Ch'au-mi-tien limestone [Blackwelder, 19070, p. 36 (part of first list 

 of fossils)], at Ch'au-mi-tien, and (C34), purplish-gray limestone about 100 feet 

 (30 m.) above the base of the Ch'au-mi-tien formation [idem], in road at northeastern 

 corner of small village near Ch'au-mi-tien; also (C54), lower part of Ch'au-mi-tien 

 limestone [idem, p. 42 (part of last list of fossils)], near top of limestone knoll two- 

 thirds of a mile (i.i km.) west of Tsi-nan; (C56), lower part of Ch'au-mi-tien lime- 

 stone, 25 feet (7.5 m.) below the top of Pagoda Hill [idem], i mile (1.6 km.) west of 

 Tsi-nan; and (C64), upper limestone member of the Kiu-lung group [idem, pp. 37 

 and 42 (first list of fossils), and fig. 10 (bed 20), p. 38], 2.7 miles (4.3 km.) southwest 

 of Yen-chuang, Sin-t'ai district, Shan-tung, China. 



Collected by Eliot Blackwelder. 



Ptychaspis ? spp. undt. Walcott. 

 Plate 17, Figures i, 6-8; Plate 21, Figures 14, 15. 



Ptychaspis sp. undt. WALCOTT, 1905, Proc. U. S. Nat. Mus., vol. xxix, p. 74. (Species referred to as in 

 first paragraph below.) 



There are several species of Ptychaspis that occur in the Upper Cambrian zone 

 that are too imperfect for description. One of these has the general form of P. 

 campe, but it differs in the exceedingly narrow fixed cheeks and flat frontal border, 

 while having the same type of pustulose surface. It occurs at Locality C47, Upper 

 Cambrian, upper part of the Ch'au-mi-tien limestone [Blackelder, 19070, fig. 9 

 (top of bed i), p. 35], at the top of a high col at Ch'au-mi-tien, Shan-tung, China. 



Free cheeks referred more or less doubtfully to the genus occur as follows : 



Plate 17, figure i ; plate 21, figure 14, at Locality C64, Upper Cambrian, upper 

 limestone member of the Kiu-lung group [Blackwelder, 19070, pp. 37 and 42 (first 

 list of fossils), and fig. 10 (bed 20), p. 38], 2.7 miles (4.3 km.) southwest of Yen- 

 chuang, Shan-tung. 



Plate 17, figure 6; plate 21, figure 15, at Locality C54, Upper Cambrian, lower 

 part of Ch'au-mi-tien limestone [Blackwelder, 19070, p. 42 (part of last list of fossils)], 

 near top of limestone knoll two-thirds of a mile (i.i km.) west of Tsi-nan, Shan-tung. 



Plate 17, figure 7, at Locality C67, Upper Cambrian, stream gravels (these are 

 taken from the wash from the mountains south of the city), used in making the 

 railroad grade, one-third mile (0.5 km.) west of the west city gate at Tsi-nan, 

 Shan-tung. 



Plate 17, figure 8, at Locality C33, Upper Cambrian, about 100 feet (30 m.) 

 above the base of the Ch'au-mi-tien limestone, 9 miles (14.4 km.) north of Sin-t'ai- 

 hien, Shan-tung, China. 



Also from Locality 050, Upper Cambrian, upper part of the Ch'au-mi-tien 

 limestone [Blackwelder, 19070, p. 36 (part of third list of fossils)], on a low spur at 

 Ch'au-mi-tien, Shan-tung, China. 



Collected by Eliot Blackwelder. 



