DENDROID GRAPTOLITES OF HAMILTON, ONTARIO. 11 



color on the surface of the stone. Its relations are somewhat doubtful, but 

 it is easily distinguished from all the other species of the family by its rootlike 

 character and slender branches (one-fortieth of an inch) often overlapping each 

 other in an irregular manner. It occurs abundantly in the Niagara limestones 

 of Hamilton, Ontario. 



In his description published in 1884, the following additional notes 

 are given : 



Fronds aggregated, resembling branching rootlets * * *. The height of the 

 individual frond does not appear to have been more than 2 or o cm., with com- 

 paratively few branches which are about three-fourths of a millimeter broad. 

 Yet the individuals appear to have grown in bunches or groups, and one speci- 

 men indicates a large number of fronds originating from a common rootstock. 

 whose branches, though only three centimeters high, cover 7 or S cm. in breadth. 



* * * More commonly the fossil consists of an irregular mass of small 

 branches lying together and occupying space on the stone not greater than 9 

 or 10 square cm. 



Dr. Giirley's description and notes are as follows: 



The specimens I have seen may be characterized as follows : Appearance of 

 po]yi:)ary as a whole, straggling and lax in the extreme, usually without any 

 evident plan, consisting of numerous very flexuous, undulate or more or less 

 undulate zigzag branches, which measure about 0.7-0.8 mm. in width, bifur- 

 cating at intervals, the resulting branchlets becoming subparallel and usually 

 about 3 or 4 mm. apart. Thecse nowhere definitely outlined. Obscure indica- 

 tions of what may have been thecre are not wanting. 



Perhaps the most characteristic single feature of this species is the irregular, 

 straggling, diffuse arrangement of the branches. In part this is owing to their 

 frequently over or under crossing one another. In one specimen (PI. 1, fig. 1) 

 the branches seem to be connected with, or arise from, a discoidal body, and I 

 believe such origin to take place, though the specimen is not well enough pre- 

 served to place the matter beyond the possibility of doubt. 



Horizon and locality. — Niagara dolomite and chert, Hamilton, Ontario. 



Spencer notes the species as very common in the dolomite. This formation 

 was not being quarried when the present collection was obtained. Hence my 

 specimens, nine in number, are all from the chert. It is worthy of note that 

 on five of these, D. problcmaticus is growing on Rhinopora verrucosa, and that 

 it in one case acquires a pseudo-structure, a serration of the margin from punc- 

 ture by the Rhinopora cells. 



Whether this is a grairtolite or not is somewhat uncertain. In some places 

 marginal indentations are visible which greatly resemble those corresponding 

 to thecse in other graptolites, but in no case are these unequivocal. Undoubt- 

 edly the si^ecies is not an Inocaulis. Among graptolites the mode of branching 

 most nearly corresponds to that in Dcndrograptus. and a provisional reference 

 is made to that genus. 



Plesiotypes.— Cat. No. 55294, U.S.N.M. ; collection of Walker Mu- 

 seum, University of Chicago, No. 13510. 



DENDROGRAPTUS PHAINOTHECA Gurley, new species. 

 Text figure 11. Plate 2, figure 2. 



The following description of this species is by Doctor Gurley: 



Polypary incomplete proximal ly, consisting only of several branches and 

 branchlets. The two branches include an angle of about 70°. Thoy are 0.5 



