204 



PALEOZOIC TIME. 



4. Articulates — (a.) Worms. — Serpulites dissolutus B., Trenton, of Montreal, 

 etc., Canada; Salterella Billingsii Saff., Tennessee, (b.) Trilobites. — Fig. 360, Asaphus 

 platycephalus (Isoielus gigas); the species is sometimes ten inches or a foot long; 

 Fig. 361, Calymene Blumenbachii Brongt. : Fig. 361 a, same rolled up, by bringing 

 the tail to the head, common; Fig. 362, Lichas Trentonensis B. ; L. cucullusM. & W., 

 from Illinois; Fig. 363, Trinucleus concentricus Eaton; Figs. 364, 365, Ayno&tus lobatus 

 H., head and tail portions magnified; 366, natural size; Illmnus crassicuudaWah]., 

 New York and Illinois. Among the other species, occur the Genera Bathyurus, Triar- 

 ihriis, Cheirurus, Bronteus, Addaspis, Dalmanites, Encrinurus, Harpes, Proetus, Pha- 

 cops ; of which, the first only is represented in the Primordial rocks. Asaphus platy- 

 cephalus St. is the only trilobite common to the Chazy and Trenton (Billings). 



(&.) Ostracoids. — Fig. 367, Leperditia fabulites? Con., natural size, from New York, 

 Tennessee, etc.; a, b, transverse and vertical sections, the specimen from Canada (L. 

 Josephiana Jones, who refers the species with a query to the fabulites of Conrad). 



2. Utica and Cincinnati Epochs. 



1. Radiates. — (a.) Polyps. — No corals have been described from the Utica 

 shale. In the Hudson Eiver beds in New York, there are species of Chmtetes related 

 to those of the Trenton, and rarely specimens of the Favistella stellata H. (Fig. 369), a 

 columniform coral related to the Columnarice, having stellate cells. This species is more 

 abundant in the ^Vest. Cyathophyllids of the genus Petraia occur, as in the Trenton; 

 also of the genus Zaphrentis, Z. Canadensis B. ; also a species of the Chain-coral, or 

 Haly 'sites, H. gracilis H., Fig. 370, from Green Bay, Wisconsin; also Syringqpora 

 obsoleta II. (Fig. 371); and species of the genus Tetradium, as Tetradium fbrosum 

 Saff., Figs. 372, 372 a ; Aulqpora arachnoidea H. 



Fisrs. 369-373. 



Fig. 369, Favistella stellata ; 370, Halysites gracilis ; 371, Syringopora obsoleta ; 372, a, 

 Tetradium fibrosum ; 373, Glyptocrinus decadactylus . 



(b.) AcalepJis.—Tig. 374 represents the Graptolitlius pnstis H., a species occurring 

 abundantly in the Hudson Eiver and Utica shales at many localities. Several other 

 species have been described by Hall. 



(c.) Echinoderms. — Crinids, Cystids, and Star-fishes occur in the rocks of the period. 



Among Crinids, the Glyptocrinus de- 

 Fig. 374. cadactylus H. (Fig. 373) is not un- 



common, occurring in New York, 

 Ohio, Kentucky and other States; 

 T r p u pns i s . a , gf) S p ec j es f the genera Dendro- 



crinus, Palceocrimis, Heterocrinus, Hybocrinus, Porocrinus, etc. Fig. 375 represents a 

 large Star-fish from the Blue limestone of Cincinnati, as figured by U. P. James, the 

 original of which was four inches across. 



