DENDROID GRAPTOLITES OF HAMILTON, ONTARIO, 



All of the species and varieties noted in the following pages occur 

 in the Niagaran limestone at Hamilton, the especial portion in the 

 section being indicated under the descriptions. These limestones 

 seem to belong entirely to the Lockport division of the Niagaran, 

 although it is possible that beds 7 to 9 of the section represent the 

 Rochester shale of western Xew York. This latter view is suggested 

 by the fact that of the six species common to the Rochester shales and 

 Lockport limestone, namely, Dktijonema retiforme^ D. polymorphum^ 

 D. siibreti forme, Cydograptus rofadenfahis, Inocaulis j)Iumulosus, 

 and Acanthograptus icalkeri, two or three are limited to the shaly 

 strata at the base of the Xiagaran limestone, while the exact position 

 of at least two more is uncertain. The essential unity believed by 

 Ruedemann to exist between the graptolite faunas of the Rochester 

 shale and the Xiagaran limestone at Hamilton is therefore more 

 doubtful. 



DESCRIPTIONS OF GENERA AND SPECIES.* 



Order DENDROIDEA Nicholson. 



Family DENDROGRAPTID^ Roemer. 



Genus DENDROGRAPTUS Hall. 



Dendrograptus Hall, Rep. Progr. Geol. Surv. Canada for 1S57, 1858. p. 143; 

 Geol. Surv. Wisconsin, 1,1862, p. 21 ; Geol. Surv. Canada, Decade 2, 1865, 

 pp. 126, 127 ; 20th Rept. New York State Cab. Nat. Hist., 1868, p. 218, 

 (rev. ed., 1868 [1870], p. 2.52).— Carruthers, Geol. Mag., V, 1868, 

 pp. 73, 130.— ZiTTEL, Handbuch d. Pal., I, 1879, p. 289.— Spencer, Trans. 

 Acad. Sci. St. Louis, IV, 1884, pp. 562, 566; Bull. Mus. Univ. State 

 Missouri, T, 1884, p. 16.— Miller, North Amer. Geol. and Pal., 1889, 

 p. 184.— James, Journ. Cincinnati Soc. Nat. Hist., XIV, Pt. 2, 1892, 

 p. 151.— Pocta, Syst. Sil. Centre Boheme, VIII, Pt. 1, 1894, p. 165.— 

 Roemer and Frech, Leth. geog., I Theil, Leith. Pal., I, 3 Lief.. 1897, 

 p. 577. — Elles and Wood, Mon. Brit. Graptolites, Pal. Soc. 1903, p. 

 xli. — Ruedemann, New York State Mus., Mem. 7, 1904, p. 578. 



Dendrograpsus Nicholson, Quart. Journ. Geol. Soc. London, XXIV, 1868, 

 p. 142; 'Mon. Brit. Graptolitidae, 1872, p. 127. 



According to Ruedemann : 



The genus DciHlrograptus was created for forms with a strong main stem 

 and a broad, spreading, shrub-like, variously ramifying frond. The theca? are 

 described as quite distinct and angular in some (the type-species of the genus, 

 D. halUanus Prout), of obscure forms in others, while in still others they are 

 shown only as round or elliptical i)its or postules. 



Genotype. — Graptolithus haUianus Prout. Upper Cambrian, Os- 

 ceola Mills, AVisconsin. The species is also known from several 

 localities in the Upper Cambrian of Tennessee and Alabama. 



"Unless otherwise stated, all of the text figures were made either by Doctor 

 Gurley or under his supervision, and are of natural size. 



