SPENCER NIAGARA FOSSILS. 565 



Getius Inocaulis diffusns, n. s. 



Inocaulis ramulosus, n. s. 



Inocaulii cervicornis, n. s. 



Inocaulis phycoides, n. s. 



Inocaulis divaricatiis (Hall), 1879. Trans. Albany Inst. 

 Genus Thamnograptus (Hall). 



ThamnograftHs{^{) bartotiensis (Spencer), 1S78. Can. Nat. 

 Genus Ptilograptus (Hall). 



Ptilograptus Joliaceus (Spencer), 1878. Can. Nat. 

 Genus Cyclog <aptus (Spencer). 



Cyclograptus rotodentattis, n. s. 



DESCRIPTION OF GENERA AND SPECIES. 



Genus PHYLLOGPATUS (Hall). 

 CJr. phullon, a leaf; grapho, I write. 



(Can. Organic Remains, Dec. ii., 1865.) 



" Frond consisting of simple or compound foliiform stipes, 

 which are celluliferous upon the two opposite sides, the margins 

 having a mucronate extension from each ceUule ; or consisting of 

 similar forms united rectangularly to each other by longitudinal 

 axes, and furnished on the outer margins with similar cells ; the 

 whole supported on a slender radicle, or combined in groups." 



One common species from the Niagara formation I have re- 

 ferred to this genus. 



PhYLLOGRAPTUS( .?) DUBIUS, nov. sp. 

 Plate I. Fig. 1. 



Stipes strong and simple, tapering at both ends by gentle 

 curvature, and traversed by a broad central depression and sur- 

 rounded by a thinner substance (black and corneous). The cells 

 are unknown, but the central axis has a jointed appearance, 

 where each joint probably indicates the origin of a cellule. Each 

 joint is a millimetre apart. The substance on each side is thin, 

 and was probably traversed by cellules. The stipes usually are 

 less than tw^o centimetres long, although sometimes double that 

 length. In thickness they usually vary from two to three milli- 

 metres, and the central axis is half the breadth of the stipe. In 

 one or two specimens a second cross-stipe appears ; this may be 

 either one preserved accidentally, or derived from the first, al- 

 though this branching form is not usual. 



