64 



BULLETIN 65, UNITED STATES NATIONAL MUSEU 



M. 



Horizon and localitt/.—magnvnn (Lockport), Hamilton, Ontario. 

 Plesioti/pes.—Cat. Xo. 55318, U.S.X.M. 



THAMNOGRAPTUS (?) MULTIFORMIS Spencer. 



ThamnograiJtus (?) muUifanni.s Spencer, Canadian Nat., X, 1S82, p. 165, 

 nomen nudum; Trans. Acad. Sci. St. Louis, IV, 1884, pp. 565, .590, pi. 6,' 

 figs. 2, 3 ; Bull. Mus. Univ. State Missouri, I, 1884, pp. 15, 40, pi. 6, hgs. 

 2, 3.— GuRLEY, Journ. Geol., IV, 1896, p. 101. 



The original description is as follows: 



Stipes simple, flexuous, and strong, usually divided into two (sometimes 

 three) branches of equal thickness. From both the undivided and divided stipe 

 a few short irregular branches originate at long unequal distances apart; and 

 these may or may not end in two free points. The texture is corneous and black, 



with the surfaces somewhat striated and im- 

 pressed with a medial line (indicating a cen- 

 tral axis?). In occasional specimens of the 

 same mode of branching, short spinelike proc- 

 esses, Ivom one-half to one millimeter long 

 and half a millimeter apart, probably indicate 

 the position of the cellules on both sides of the 

 1 1 ranches. 



There is considerable variation in the size 

 -)f these organisms. The larger specimens are 

 4 or 5 cm. long, and the stipes are usually 

 about 1 mm. thick; however, some of the 

 specimens, that I have referred here, have not 

 more than half that size. In the larger speci- 

 mens the branches are usually about half a 

 centimeter apart. 



In the rocks of the Niagara formation nu- 

 merous fragments of organism of the graptolite family occur. Vast numbers, 

 consisting of thick broken stipes, often flexuous, with one or two branches, or 

 those with dichotomous terminations, are found, and can not be referred to liny 

 species described. Yet they so closely resemble the better specimens of this 

 species that I have placed them here, although a further study might separate 

 some of them from this species. 



Formation and locality.— Fragments of this species occur somewhat abun- 

 dantly in the Niagara dolomitic rocks at Hamilton, Ontario. 



Of this species Doctor Giirley says : 



After many endeavors to recognize this spec-ies I have failed to find anything 

 which I could confidently refer to it. As far as my experience goes nothing 

 which has any definite structure resembles it. The only things which seem to 

 approximate it are the most fragmentary specimens, too indefinite to be re- 

 ferred anywhere else. A perusal of Spencer's description also leads me to 

 suspect (but I do not assert it) that this species is not much more than a 

 dumping ground for fragments. Certain it is that from time to time series 

 after series of fragments (and at this horizon fragments are unusually and 

 dispro[)ortionately numerous) otherwise unplaced were identified as this spe- 

 cies, but eventually all except the worst were successfully referred elsewhere. 

 This species must then stand on Spencer's diagnosis and figure. 



FiG.s. yo, 91. — Thamnogkaptus ? 



MULTIFORMIS SPEN'CER. COPIES 



OF Spexcer^s figures. 



