274 



PALEOZOIC TIME. 



Scudder ; and Dawson thereupon observes that " the trill and hum of 

 insect life must have enlivened the solitudes of the strange old Devo- 

 nian forests." Insects appear to have been the only winged life of 

 the Devonian and Carboniferous ages. 



Vertebrates are represented only by fishes ; and the species are of 

 the Selachian (or Shark), Ganoid, and Placoderm groups, as in the Cor- 

 niferous era. One of the Placoderms from the Black shale of Ohio, 

 called Dinichtliys Hertzeri by Newberry, had a head three feet long 

 by two broad, and under jaws two feet long : the fish could hardly 

 have been less than twenty feet in length. The remains are very 

 numerous. A fin-spine ( Gtenacanthus vetustus) a foot long, from the 

 same shale, belonged to a shark probably fifteen feet long. 



Characteristic Species. 



1. Radiates. — Fig. 535, the Coral Heliophyllum Halli E. & H., common in the 

 Hamilton, at Moscow, York, and elsewhere, and found also in England. The Encrinal 

 limestone is made up of fragments of crinoidal columns. 



2. Mollusks. — (a.) Brachiopods. — Fig. 536, Atrypa aspera Dalm., also Euro- 

 pean; 537, A. reticularis, regarded as the same species as that of the Corniferous period, 

 but usually much larger and fuller, being sometimes nearly two inches broad; 538, 

 Tropidokptus carinatus H., in New York, Illinois, Iowa, Europe; 539, Spirifer mucro- 

 natus Con., very common; 540, Athyris spiriferoides H. {Atrypa concentrica of Conrad), 

 — it has the spire internally of a Spirifer ; 541, Spirifer (Ambocozlia) umbonatus ; 542 

 Chonetes setigera H., found in both the Marcellus and Genesee shales; 543, Productus 

 (Productella) subalatus H., Rock Island, 111. A shell closely like the S. umbonatus, but 

 higher, occurs in Iowa and Illinois, and is named Cyrtina umbonata by Hall. Spirifer 

 granuliferus H. is a large Hamilton species, having a granulated surface. 



(b.) Lamellibranchs. — The species are often of large size; but none yet described 

 have a sinus in the pallial impression. Fig. 544, Orthonota undulata Con. ; 545, Ptertnea 

 jlabella Con. ; 546. Grammysia bisulcaia Con. {Hamiltonensis of Verneuil), — also Euro- 

 pean, in the Eifel ; 547, Microdon bellistriatus Con. 



(c. ) Gasteropods. — A few species have been described. They are all without a beaked 

 apei'ture, like those of older time. The Bellerophon patulus H. is a broad species of 

 the genus, with a flaring aperture. Platyceras ventricosum Con., Isonema {Holopea} 

 depressa M. & W. 



(d.) Cephalopods. — Fig. 548, Goniatites Marcellensis Van., a species sometimes a foot 

 In diameter, occurring in the Marcellus shale; 548 a, dorsal view. Two small species, 

 the G. uniangularis and G. punctatus, are reported by Conrad from the Hamilton beds. 

 The genus Orthoceras is represented by a few species of moderate size ; there are also 

 Gomphoceras turbiniforme M. & W., Cyrtoceras sacculum M. & W., and Gyroceras(f) 

 constrictum M. & W., in Illinois and Indiana. 



3. Articulates.— (a.) Crustaceans. — The Trilobites Phacops bufo (Fig. 549) and 

 Dalmanifes Boothii H. (D. calliteles) (Fig. 550, representing the posterior extremity) are 

 common in the Hamilton beds; also Phacops rana Green. Eurypterus pulicaris Salter, 

 a minute species, occurs at St. John, New Brunswick, and with it a peculiar crustacean, 

 Macrural in habit, the Amphipeltis paradoxus Salter. 



(b.) Insects. — At St. John, N. B., besides the Platephemera antiqua Sc. (Fig. 550 A.), 

 there are two other Neuropters with a spread of wing of 3J inches, and a fourth, the 

 Xenoneura antiquorum Sc, with the same 2 J inches; this last is the one having the 

 8tridulating organ alluded to above. 



4. Vertebrates. — The fossil fishes of the Hamilton rocks are of several genera 

 and species. In the Gaspe" sandstones occur remains of Cephalaspis, and " apparently 



