SPENCER NIAGARA FOSSILS. 569 



rise to lateral branchlets rather than bifurcations. The branches 

 are short and slender, not exceeding one-third of a millimetre in 

 thickness. The surface is striated ; the cellular openings are 

 minute and oval, but usually indistinct. Fig. 6a represents an 

 enlarged branch. 



This graceful little frond is less than two centimetres broad, 

 and one and a quarter centimetres high. 



Formaiion and LocalUy. — It occurs in the Niagara dolomite at 

 Hamilton, Ontario. 



DeNDROGRAPTUS PR^GRACILIS, nov. sp. 

 Plate I. Fig. 7. 



Frond difliise. The branches, few in number (three or four), 

 originating from a long slender stipe, with each sending oft' small- 

 er, very slender branchlets. Sui-face striated, and celluliferouson 

 one side. Branches about quarter of a millimeter broad and di- 

 verging considerably. The umbeliferous summit is about as 

 broad as high (measuring one and a half centimetres, besides the 

 long stipe). 



The mode of branching and general appearance of this fossil 

 closely resembles D. gracilis of the Quebec group, only it is 

 much smaller. 



For}naiio7i and Locality. — It occurs in the Niagara dolomite at 

 Hamilton, Ontario. 



Dendrograptus spinosus, nov. sp. 



Plate I. Fig. 8. 



Frond small and shrub-like, with long flexuous stipe extending 

 to the summit, and giving oft' branches, usually alternate and at 

 unequal distances, and diverging from each other at considerable 

 angles. From both stipe and branches there are numerous spine- 

 like branchlets, which sometimes have dichotomous terminations. 

 The surface is striated, but the cellular structure is not preserved. 

 The branches vary from one-third to one-half of a millimetre (in 

 different specimens) in thickness, with somewhat greater dis- 

 tance between. The frond is usually twice as long as wide, and 

 varies from one and a half to two centimetres higb. 



Formation atid Locality. — This graceful little fossil is found in 

 the "cherty beds" of the Niagara dolomite, at the "Jolly-cut road," 

 at Hamilton, Ontario. 



