218 
tant part in it throughout. The flora of the Potomac Formation 
is represented in part by the most ancient dicotyledonous angio- 
sperms of which we have any knowledge—archaic types, in which 
the outlines of subsequent modern genera are foreshadowed. The 
following new species are figured: Sc/eropteris Vernonensis, Zamia 
Washingioniana,.Casuarina Covillei, Sagittaria Victor-Masoni, An- 
tholithus Gaudium-Rosae, Populus Potomacensis, P. auriculata and 
Celastrophyllum Hunteri. 
As a demonstration of the value of palaeobotany in determin- 
ing the stratigraphic relations of beds this contribution is a master- 
piece and. its appearance will be welcomed by all workers in the 
geology and palaeontology of the central plain region. 
A. FA. 
Proceedings of the Club. 
TursDAY EVENING, APRIL 9QTH, 1896. 
President Brown in the chair and thirty members present. 
Miss Fanny A. Mulford and Mr. Charles W. Mulford were 
elected active members. 
Dr. Schneider read his announced paper, “The Uses of 
Lichens,” giving an instructive account of the past and present 
uses of these plants in medicine and the arts. 
The next paper was that of Mr. P. A. Rydberg entitled “ Pre- 
liminary notes on a Revision of the North American Species of 
-Potentilla and related Genera.” This was accompanied by 
numerous specimens and drawings and elicited remarks from the 
President and Mrs. Britton. 
Mrs. Britton then read a paper, « Notes on Mexican Mosses,” 
giving a short historical account of the various collections of 
mosses which have been made in Mexico and in comparing the 
number of genera and species common to Mexico and the United 
States. Numerous specimens were exhibited. 
WEDNESDAY EVENING, APRIL 29TH, 1896. 
President Brown in the chair and sixty-four persons present. 
Dr. Britton announced his associates on the Field Committee 
