Vol I. Grabau — Ordovician Fossils from North China (i) 33 



The earlier whorls, some of which are shown on the same rock fragment, have 

 the normal character of the young of P. dorothea, which is also essentially like that of the 

 adult P. derwiduii. 



Horizon and Locality: This variety occurs in the upper heds of the Machiakou 

 or Actinoceras limestone of Chaokouchuang, where it was collected hy the Survey party. 



Genus LlOSPIRA Uli-ich & Scofield 

 Liospira barbouri Grabau (sp. nov.) 



P]ale III, Fjgs. 14a, b., 15a - c. 



Shell of medium size but somewhat higher spired than in the majority of species 

 of that genus. Height of spire somewhat variable, the apical angle ranging from 110° in 

 the lowest to 95° in the highest spired individual. AVhorls subrhomboidal, with a gently 

 concave shoulder and a sharp shoulder angle which varies from 60° in the more strongljr 

 conical to 55° in the more depressed forms. Lower part of the whorl very gently convex 

 or almost flat; Avith a sharp angle at the rather large umljilicus. 



Perii^heral band on the outer margin of the shoulder fairly well defined by a low 

 but sharp carina or spiral, the succeeding whorl embracing to the outer edge of the 

 peripheral band, i. e. to the shoulder anglC; so that the suture is not depressed. Lines of 

 grow^th nearly vertical or slightly oblique backwards in the upper half of the shoulder, 

 after which they are strongly deflected backM'ard to the peripheral band which tliey cross 

 with a definite curve, producing a pronounced marginal notch (Plate III, Fig. 15c). 

 Aperture not fully preserved in tlie known specimens. 



This species has the rather flat base and subtrochoidal form of a Eucunia, but the 

 sharp shoulder angulation, the usual concavity of the shoulder, tlie large umbilicus with 

 angular margins, and the slightly defined band on the peripheral margin of the shoulder, 

 indicate its relationship to the genus Liospira. The character and position of the 

 peripheral band, and the deep notch are features also suggestive of Euconia. 



I am not acquainted M'ith any American or European species with which this 

 speeii'S is likely to be confounded. It lias many of the characters of L. vltruciu (Billings) 

 of the Middle and early Upper Ordovician (Stones Kiver to Trenton) of Canada and the 

 United States, but the spire is higher and the apical angle therefore less, in our species, 

 while the shoulder angle of our form is also sharper and the lower part of the whorl 

 flatter. 



