442 



PALEOBOTANY. 



be indubitable plants. They are thus described by Dr 

 Dawson in a note communicated to the author : — 



1. Buthotrephis Harknessii.-^This consists of what have been cylindrical 

 branches, given off from a central stem, and producing a few branchlets 

 in the manner of Pinnularia. Under the microscope the branches show 

 a vesicular structure ; but this I believe to have been produced by the 

 weathering out of minute globular concretions, probably of calcareous 

 matter. The appearances are rather those of roots or slender herbaceous 

 .stems than of Algae. If found in the Coal-measures it would probably 

 be regarded as an obscure Pinnularia. 



Fig. 697. — Licrophyais Uttawaensis, a " Fucoid " from tlie Trenton Limeston 

 (Lower Silurian) of Canada. (After Billings.) 



2. Bitthotrephis radiatus. — This shows radiating branchlets or leaves 

 (fig. 698), with the same vesicular structure as the preceding, and having 

 some resemblance to the whorls oi Annularia, though without any midrib. 



It is quite possible that both of the above may belong to the same 

 species. If a land-plant, allied to Annularia, the first may represent the 

 roots or sub-aquatic stems, and the second its whorls of leaves. If an 

 Alga, the first may represent branching fronds, and the latter the fructi- 



