Page:Walcott Cambrian Geology and Paleontology II.djvu/142

86 limb, larger palpebral lobes, and more elongate glabella. From Chuangia nais and C. fragmenta it differs in its longer palpebral lobes and in the outline of the glabella.

Formation and locality.—Upper Cambrian: (C11) crystalline limestone 60 feet (18 m.) above the base of the uppermost limestone member, 2.1 miles (3.4 km.) southwest of Yen-chuang. Sin-t'ai District, Shan-tung, China.

Collected by Eliot Blackwelder.

This genus is proposed to include a group of small trilobites represented by Agraulos agenor Walcott. The cranidium is strongly convex; glabella truncato-conical, tumid, and with only a trace of glabellar furrows; occipital ring narrow at the sides, broadening rapidly toward the center, convex, and extending backward into an obtuse spine. Frontal limb very narrow and passing almost without any line of demarcation into the rather broad, slightly convex frontal margin of the cephalon. Fixed cheeks tumid, about half as wide as the glabella and with small palpebral lobes midway of their length. Postero-lateral limbs rather short and marked by a deep, narrow, intermarginal posterior furrow that separates a narrow, rounded margin.

Genotype.—Agraulos agenor Walcott (pi. 15, fig. 7). A second species, Levisia adrastia (Walcott) has the same generic characters. Its surface has the same pitting and in addition a few relatively large, scattered granules.

Two species of this genus occur with an Upper Cambrian fauna in the boulders of the conglomerate at Point Lévis, opposite Quebec, Canada. The first I shall give the name of Levisia richardsoni in recognition of the fine collecting work done by Mr. J. Richardson under the direction of Sir William E. Logan.