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 [Jsoielus gigas); the species is sometimes ten inches or a foot long; 

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

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

 from Illinois; Fig. 363, Trinucleus concentricus Eaton; Figs. 364, 365, Agnostus lobatus 

 H., head and tail portions magnified; 366, natural size; Illcenus crassicaudaWahl., 

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

 thrus, Cheirurus, Bronteus, Acidaspis, Balmanites, 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). 



(b. ) Ostracoids. — Fig. 367, Leperditia fabulites f 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 River beds in New York, there are species of Chaitetes related 

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

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

 abundant in the West. 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 

 Ilalysites, H. gracilis H., Fig. 370, from Green Bay, Wisconsin; also Syringopora 

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

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



Figs. 369-373. 

 370, 



Fig. 369, Favistella stellata ; 370, Haly sites gracilis ; 371, Syringopora obsoleta ; 372, 

 Tetradium fibrosum ; 373, Glyptocrinus decadactylus. 



(b.) Acalephs. — Tig. 374 represents the Graptolithus pristis H., a species occurring 

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

 6pecies 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- 



*W-^sw«mW«» —11 mUl9l„Mis^^* = ~~ Ohio, Kentuckv and other States; 

 Graptolithus pristis. ^ gpecies of " the genQm Dendr0 _ 



C7'inus, Palmocrinus, Heterocrinus, ffybocrinus, 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. 



