SPENCER NIAGARA FOSSILS. 571 



Callograptus niagarensis, nov. sp. 



Plate I. Fig. 9. 

 Callograptus niagarensis (Spencer), Can. Nat., vol. viii., No. 8, 1S78. 



Frond flabellate, with slender branches more or less parallel ; 

 form nearly semicircular, with branches radiating from a com- 

 mon axis. In texture it is corneous, with the surfaces of the 

 flattened branches marked with striations, appearing like cell- 

 impressions, while on the reverse side minute oval pits or points 

 indicate the apertures of the cells, of which there are as many as 

 twelve in a centimetre, the longest diameter of the cell-orifice be- 

 ing about half a millimetre. 



The frond does not usually exceed four centimetres in breadth, 

 being broader than high. The branches are a little less than 

 half a millimetre broad, with spaces between them sometimes 

 exceeding a millimetre in breadth. 



This species is easily distinguished from Dictyonema by the 

 absence of cross-bars, and by the branches of frond being free. 

 By the mode of branching, this species can be distinguished from 

 Dendrograptus even if the cellules are obscured. 



Formation and Locality. — This species occurs in the Niagara 

 dolomites and shales at Hamilton, Ontario. 



Callograptus granti, nov. sp. 



Plate 1. Fig. 10. 



Frond originating from a single stipe ; branches slender, and 

 bifurcating two, three, or four times, and principally originating 

 near the common radicle. In spreading gently above in undula- 

 tions the branches are more or less parallel and situated closely 

 together, and are connected occasionally with exceeding fine 

 transverse bars. The texture is corneous, with the surface ob- 

 liquely striated and marked with ellipsoid pits, which in some 

 places indicate the orifices of the cells, of which there v/ere about 

 two for every millimetre of length of branch. (See PI. i, fig. loa.) 

 The branches are rarely connected by minute cross-bars. 



The general outline is that of a regular oval form, whose 

 length, in the most perfect specimens, is three centimetres (be- 

 sides the common stipe, which extends another centimetre), and 

 breadth, two centimetres. The branches are not more than a 



iv — 4 2 [May, 18S4. 



