586 TRANS. ST. I^OUIS ACAD. SCIENCE. 



plumulose appearance ; structure corneous with a central axis, 

 and the surface covered with minute points representing the cell- 

 apertures. 



This frond somewhat resembles /. plumulosus^ but is slighter, 

 and the branches (not exceeding 1.5 mm. in thickness) are much 

 more numerous, and proceed from a single stipe. The type spe- 

 cimen has a height of eight and a breadth of six centimetres. 



Formation and Locality. — This species occurs in the Niagara 

 limestones at Hamilton, Ontario. 



Inocaulis problematicus, nov. sp. 



Plate 5. Fig. 3. 

 Inocaulis problematicus (Spencer). Can. Nat., vol. viii., No. S, 1S7S. 



Plant-like, with small slender bifurcating branches ; fronds ag- 

 gregated, resembling branching rootlets ; texture corneous with 

 irregular corrugations. The height of the individual frond does 

 not appear to have been more than two or three centimetres, with 

 comparatively few branches which are about three-fourths of a 

 millimetre broad. Yet the individuals appear to have grown in 

 bunches or groups, and one specimen indicates a large number 

 of fronds originating from a common rootstock, whose branches, 

 though only three centimetres high, cover seven or eight centime- 

 tres in breadth. 



The texture is generally poorly preserved, and is often rep- 

 resented only by stains on the surface of the stone. More com- 

 monly the fossil consists of an irregular mass of small branches 

 lying together and occupying space on the stone not greater than 

 nine or ten square centimetres. 



The relation of this species is doubtful, but it is of such com- 

 mon occurrence that it becomes necessary to notice it. 



Forfnation and Locality. — This is a common species in the dolo- 

 mite limestones of the Niagara formation at Hamilton-cut. 



Inocaulis diffusus, nov. sp. 



Plate 5. Fig. 4. 



Frond originating in a single stipe at base, and rising above in 

 numerous widely extended branches, averaging about a millime- 

 tre in breadth, with dichotomous terminations ; branchlets origi- 

 nating more frequently on one side than on the other. Texture 



