^^'^^ I- Grabau — Ordovi'cian Fossils from North China (i) 27 



^ Lophospira trochiformis Grabau (sp. nov.) 

 Plate III Figs. 5a, ob. 



Shell with trochiform spire, the whorls embracing to the peripheral angulation. 

 Shoulder concave, the periphery formed by a round band delimited by linear depressions 

 above and below. Body of whorl without carina, concave below the peripheral band but 

 convex for the greater portion; umbilicus small. Apical angle about 75*', shoulder angle 

 1000. 



This species resembles L. morrisi, but is more strongly embracing, so as to 

 entirely cover the preceding whorl. There is, further, no indication of an accessory carina 

 on the body of the whorl. 



Horizon and Locality: In tlie upper part of the Actinoceras or Machiakou 

 limestone at Tangshan. 



Lophospira acuta Grabau (sp. nov.) 

 Plate III Figs. 6. 



Shell small, high-spirod, apical angle about 57 degrees, wliorls embracing to lower 

 carina, which is pronounced and sharp. Shoulder concave, characterized 1>3' revolving 

 spirals, and forming an acute angle with the Iwdy of the whorl. Shoulder angle sharp. 

 There are indications of rather sharply pronounced growth-lines which cancellato the 

 spirals. Umbilicus minute. 



This species differs from L. pulchelliformis, in the more acute shoulder angle, and 

 in the sharp peripheral and lower carina. The apical angle is also somewhat smaller in 

 L. acuta than in L. pulchelliformis. 



This species resembles in form, acuteness of whorl, and sharpness of carinte the 

 American L. acuminata (Ulrich and Scofield) from the Upper Ordovician (Richmond) of 

 tlie central United States, and like that form, appears to have strong groA\'th lamellte. 

 Our species is however characterized by a minute umljilicus, which is absent in the 

 American species. 



HoKizoN AND Locality : This species was collected by the Survey party in the 

 upper Actinoceras limestone (Machiakou limestone) near Chaokouchuang, province^of 

 Chihli (Kaiping coal basin). Its age is early Upper Ordovician. Cat. Mus. Geol. Survey 

 Nos 47 and 48. 



