l82 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 64 



ACROCEPHALITES ? VULCANUS (Billings) 

 Plate 26, fig. 2 



Conocephalites vulcanus Billings, 1861, Rept. Geol. Vermont, Vol. 2, p. 



952, fig. 357. (Original description and figure.) 

 Conocephalites vulcanus Billings, 1863, Geol. Canada, 1863, p. 286, fig. 296. 



(Original description and illustration repeated.) 

 Conocephalites vulcanus Billings, 1865, Pal. Fossils Canada, Vol. i, p. 14, 



fig. 17. (Pamphlet of 1861 republished.) 

 Ptychoparia vulcanus (Billings) Walcott. 1886, Bull. U. S. Geol. Survey, 



No. 30, p. 198, pi. 26, figs. 4, 4a. (Republished Billings's description 



with comment and gives two figures.) 

 Ptychoparia vulcanus (Billings) Walcott, 1891, Tenth Ann. Rept. U. S. 



Geol. Survey, p. 653, pi. 96, figs. 4, 4a. (Republished figures of 1886.) 



Numerous more or less distorted casts of the cranidium of this 

 species occur in a fine decomposed ferruginous and slightly calcare- 

 ous sandstone. The matrix of the casts suggests a granulated 

 surface, but this may result from its fine sandy character. Although 

 the median boss on the frontal limb suggests a reference to Acro- 

 cephalites, the nearly smooth glabella and strong frontal rim point 

 to some other genus that may be the representative of Acrocephalitcs 

 in the Lower Cambrian formations. Both Mr. Billings and I failed 

 to note the boss in front of the glabella. It is well defined in four 

 specimens before me and quite small on two others. 



The largest specimen of the cranidium has a length of 6 mm. 



Formation and locality. — Lower Cambrian: (25) Sandstone just 

 above Parkers Quarry, near Georgia; also (26) northeast of the 

 Corman farm buildings, east of Highgate Springs, both in Franklin 

 County, Vermont. 



Genus ALOKISTOCARE Lorenz 



Alokistocare Lorenz, 1906, Zeitschr. deutsch. geol. Gesellsch., Bd. 58, p. 62. 



General form of the dorsal shield elongate-oval, narrowing gradu- 

 ually from the ratl^er large cephalon to the small pygidium. 



Cephalon with flattened marginal rim produced into spines at the 

 genal angles. A low rounded boss occurs in front of the glabella 

 that usually extends across the frontal limb onto the frontal rim so 

 as to interrupt the furrow delimiting the two. On A. labrosum (pi. 

 25, figs. 5, 5a) the boss does not extend onto the frontal limb, and on 

 A. ? prospecteiise (fig. 8) and A. linnarssoni (figs. 7, ya) it only par- 

 tially interrupts the indistinct frontal furrow. Palpebral lobe and eye 

 of medium size; palpebral ridge strongly outlined across the rela- 

 tively broad free cheek. Gfabella defined by strong dorsal furrows 



