DENDROID GRAPTOLITES OF HAMILTON, ONTARIO. 



49 



limestone at Hamilton is here reproduced in text figure 98 [59] by a pen 

 drawing made under Gurley's supervision. In Plate II, figure 4 [text fig. 61] 

 a portion of the same specimen which is partly weathered has been refigured 

 to show the thecte. Where in unweathered specimens the perisark is partly 

 broken away [as in text fig. 60], the circular sections of the composing tubes 

 can be seen and the whole branch is found to be composed of apparently equal 

 tubes. 



The rhabdosome, when moi'e complete than in the specimens hitherto men- 

 tioned, forms a dense mass of overlapping branches, which on account of the 

 frequent dichotomies and later reapproachments of the branches assumes to 

 some extent the aspect of a huge Desmograptus. 



We have been unable to see in any of our or Spencer's rhabdosomes the 

 central axis which he asserts to have observed in a number of specimens, and 

 we doubt, from the general structure of this form, that such a thing as a 

 central axis existed. 



Horizon and localitij. — The type is from the Niagara shale of New 

 York, and the specimen here floured (text fig. 59) from tlie same 

 horizon at Hamihon, Ontario. 



Plesiotype.—C-Ai. No. 51281, U.S.N.M. 



INOCAULIS RAMULOSUS Spencer. 



Inocaulis ramulosa Spencer, Canadian Nat., X, 1882, p. 16.5, nomen nudum. 



Inocaulis ramulosus Spencer, Trans. Acad. Sci. St. Louis, IV, 1884, pp. 

 565, 588, 589, pi. 6, fig. 1; Bull. Mus. Univ. State Missouri. I, 1SS4, 

 pp. 15, 38, 39, pi. 6, fig. 1.— (JuRLEY, Jouru. GeoL, IV, 1896, pp. 99, 309. 



Fig. 63. — Inocaulis ua.mulosus Spencer. Copy of Spencer's figure. 



The original description by Spencer is as follows : 

 Frond consisting of numerous flattened bifurcating branches, originating 

 in and radiating from a common radicle, composed of solid chitinous matter; 



