(30) 
Transform (29) by the relation 
1 - cos.m0 
^ _ 1 + COS .7il0 
The equation (31) is, therefore, of the form given in 
art. (7). 
“ Notice of a Fossil Plant found at Laxey, in the Isle of 
Man ” by E. W. Binney, F.R.S., F.G.S., President. 
Many years ago the late Sir William Logan drew atten- 
tion to the occurrence of fossil plants in the Devonian 
strata of Canada, and Professor J. W. Dawson, F.RS., in the 
Quarterly Journal of the Geological Society, in vols. XV. 
and XVIII., described and figured some of these specimens. 
Amongst them was a plant which he designated Psilophytum. 
Dr. S. S. Scoville has since discovered the remains of plants 
in the Lower Silurians at Longstreet Creek, near Lebanon, 
Ohio, which Professor Newberry considered as the casts of 
some large fucoids or marine plants. Count Saporta has 
found the branch of a fern in the Silurian schists or slates 
of Angers, France. Professor Leo Lesquereux, to whom we 
owe so much for his labours in investigating the fossil plants 
of the United States, in a paper read before the American 
Philosophical Society, October 10th, 1877, has described 
and figured a plant from the Lower Heldeberg Sandstone, 
Michi gan, under the name of Psilophytum cornutum. 
In a paper read by myself before this society on the 26th 
December, 1876, 1 stated that after some years’ search I had 
not been able to find the Palceochorda major mentioned by 
Professors Harkness and Nicholson as occurring in the Manx 
schists in such a state of preservation as to be certain of its 
