288 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 127 
PETROCRANIA HALLI (Sardeson) 
Plate 25, D, figures 11, 12 
Crania halli SarpEson, Minnesota Acad. Nat. Sci., Bull. 3, p. 328, pl. 4, figs. 8-10, 
Apr. 9, 1892. 
Craniella ulrichi HAtt and CriarKE, Pal. New York, vol. 8, pt. 1, p. 181, pl. 4,I, figs. 1, 2, 
1893. 
C. ? ulrichi Hall and Clarke, WINCHELL and ScHUCHERT, Geol. Minnesota, vol. 3, p. 375, 
pl. 20, figs. 38, 30, 1893. 
Specimens of P. halli labeled by Dr. Sardeson and deposited in the National 
Museum have all the significant characters of P. ulrichi. The two species are 
here regarded as synonyms, and the name P. halli has precedence. Much un- 
certainty exists about the dates of some of the Minnesota species, but in this case 
it seems clear that Sardeson’s name should supercede P. ulrichi. The letter of 
transmittal of Pal. New. York, vol. 8, pt. 1, is dated May 1892, whereas Sarde- 
son’s paper appeared in the early part of April. Winchell and Schuchert state 
that it “. . . is well known, part 1 of that volume [Pal. New York, vol. 8] was 
printed nearly two years before it was published.” As the validity of a species 
depends on its date of publication, the fact mentioned by Winchell and Schuchert 
has no bearing on the standing of the species. 
Figured specimens.—24218a, 45218a. 
Horizon and locality—Decorah formation (Spechts Ferry member—Sticto- 
porella bed, to Ion member—Phylloporina bed) in Minnesota: St. Paul and 
vicinity. 
PETROCRANIA HAMILTONIAE (Hall) 
Plate 25, E, figures 13, 14 
Crania hamiltoniae HALL, 13th Rep. New York State Cab. Nat. Hist., pp. 76, 77, figs. 4, 5, 
1860; Pal. New York, vol. 4, p. 27, pl. 3, figs. 17-23, 1867. 
Impressions of the interior of this species are introduced to show the pallial 
marks and musculature for comparison with Ordovician species. 
Figured specimens.—116834b,c. 
Horizon and locality—Basal Ludlowville (Stone Mill member) in New 
York: At 1,265 feet elevation on the road 1 mile southwest of Randallsville, 
Morrisville (15’) Quadrangle. 
PETROCRANIA INFLATA Cooper, new species 
Plate 25,1, figures 24, 25; plate 25, J, figures 26-35; plate 26, F, figures 14, 15 
Small to medium size for the genus, forming a rounded ellipse in outline with 
the width slightly greater than the length. Profile an irregular cone with the 
apex pointing posteriorly and overhanging the posterior slope. Apex located 
at about one-fourth the length from the posterior margin. Posterior slope steep 
and slightly concave; anterior slope steep and strongly convex in profile. Sur- 
face marked by concentric undulations, in some instances with irregular patterns 
induced by the ornamentations of the host. 
