Parr II. Src. ii. §2.] SILURIAN. 669 
by star-fishes of the genera Palzaster and Stenaster; the annelides by 
Serpulites, and numerous burrows and tracks; the trilobites byes 
genera, of which the most important for their stratigraphical value 
are Acidaspis (8 species), Ampyx (6), Agnostus (5), Asaphus (6), Caly- 
mene (8), Cheirurus (6), Homalonotus (4), Illenus (13), Lichas (6), Phacops 


Fic. 325.—Grovur oF Carapoc Fossits. 
a, Porambonites intercedens (Pander); 6, Orthis hirnantensis (McCoy); ¢, Lingula 
longissima (Pander ?); d, Strophomena grandis (Sby.); e, Orthis plicata (Sby.); 
f, Orthis calligramma (Dalm.); g, Crania divaricata (McCoy); hk, Triplesia (?) 
maccoyana (Day.); 7, Atrypa (?) Headii (Billings) (2); 7, Atrypa marginalis (Dalm.) ; 
k, Discina oblongata (Portl.); 1, Ambonychia prisca (Portl.); m, Palzarca billing- 
siana (Salt.) ; », Rhynchonella nana (Salt.) ; ¢, Cleidophorus ovalis (McCoy). 
(13), Remopleurides (8); the ostracods by Beyrichia, Leperditia, Cythere, - 
Primitia, and Entomis; the polyzoa by Fenestella, Gilauconome, and 
Piilodictya; the brachiopods by Atrypa, Rhynchonella, Leptena, Orthis 
(41 species), Strophomena (19), Discina, and Lingula ; the lamellibranchs 
by Ctenodonta (17 species), Orthonota (5), Modiolopsis (16), Pterinea 
