10 BULLETIN 65, UNITED STATES NATIONAL MUSEUM. 



■Museum collection, but it presents no features not already given in 

 the above description. 

 Plesioti/pe.— Cat Xo. 55293, U.S.N.M. 



DENDROGRAPTUS SPINOSUS Spencer. 

 Text figure 5. 



Dendrograptus spinosus Spencer, Can. Nat., X, 1SS2, p. 165, nomen nudum; 

 Trans Acad. Sci. St. Louis, IV, 1884, pp 564, 569, pi. 1, fig. 8; Bull. 

 Mus. Univ. State Missouri, I, 1884, pp. 14. 19. pi. 1, fig. 8.— Miller, 

 Nortli Amer. Geol. and Pal., 1889, p. 185. — Gurley, Journ. Geol., IV, 

 189G. pp. 95, 308. 



The original description is as follows: 



Frond small and shrublike, witli long flexous stipe extending to tlie summit, 

 and giving off branches, usually, alternate and at unequal distances, and diverg- 

 ing from each other at considerable angles. From both stipe and branches 

 there are numerous spinelike branchlets, which sometimes have dichotomous 

 terminations. The surface is striated, but the cellular structure is not pre- 

 served. The branches vary from one-third to one-half of a millimeter (in 

 different specimens) in thickness, with somewhat greater distance between. 

 The frond is usually twice as long as wide, and varies from li to 2 cm. high. 



Formation and locality. — This graceful little fossil is found in the cherty beds 

 of the Niagara dolomite, at the " Jolly-cut road," at Hamilton, Ontario. 



Doctor Gurley based the following description upon a specimen in 

 the Spencer collection: 



Portion of polypary seen about 15 by 10 mm., consisting of branches which 

 measure 0.25-0.3 mm. None were seen as large as 0.5 mm, (as reported by 

 Spencer). In their course they zigzag slightly, the spines proceeding from the 

 convex angle of each bend. The stems seem to be somewhat wider at each 

 angle, to contract above, and then again gradually widen up to the next angle, 

 thus seeming as though formed of a series of similarly oriental cones ; but the 

 material is not perfectly satisfactory on this point. Division taking place 

 irregularly, either by obllijue lateral branching, or by dichotomy, not regularly 

 unilateral, regularly bilateral, or regularly alternate. Thecie invisible. 



DENDROGRAPTUS ? PROBLEMATICUS (Spencer). 



Text figure 6. Plate 1, figures 1, 2. 



Inocanllfi ? prohlematiea Spencer. Can. Nat.. VIII, 1878, pp. 4.58. 461; X. 

 1882, p. 165; Trans. Acad. Sci. St. Louis, IV, 1884, pp. 564, 586, pi. 5, 

 fig. 3; Bull. Univ. Missouri, I, 1884, pp. 14, 30, pi. 5, fig. 3.— Miller. 

 North Amer. Geol. and Pal., 1889, p. 194. — Gurley, Journ. Geol., IV, 

 1890, pp. 99, 309. 



Doctor Spencer's original description is as follows: 



Plantlike, with numerous slender bifurcating branches, radiating more or 

 less from a common center, and resembling the branches of rootlets; texture 

 corneous with irregular corrugations. 



This species is of common occurrence, and is not easily mistaken for any 

 other. The texture is not well preseved, appearing often as mere stains of dark 



