23 
“The Geognostic Relations of the Flora of North Wales”— 
By Mr. J. LLOYD WILLIAMS. 
Read before the Botanical Section. 


I,—OBJECTS OF THE LECTURE— 
I. To show that the Geological factor, particularly the 
structure aud chemical constituents of the underlying rocks, 
exercises a greater influence on the distribution of plants than 
is generally conceded ; 
2. Seeing that North Wales has such a variety of rocks, the 
Flora of which can be easily compared and contrasted within 
small areas, to see whether it be not possible for Botanists to 
work the district systematically and to put on record the 
observations so made. 
Ii.—The relation of plants to inorganic food substances—particularly lime, 
potash, and phosphoric acid—briefly explained, 
III,—Illustrations of the dependence of the Flora on the Geological forma- 
tions given from the various Counties— 
1. ANGLESEY —The Gneiss and Schists, the old Red Sand- 
stone, the Lower Silurian and the Limestone formations. 
2. CARNARVONSHIRE—The Slates and Sandstones, the 
Volcanic Rocks (particularly the Acid Lavas), the Diabases and 
the Calcareous Volcanic Ashes of the Snowdon district, the 
Limestones of the Great Orme, and the Drift in various parts of 
the County. 
3. DENBIGHSHIRE—The Wenlock Shales between the 
Conway and the Clwyd Valleys, the Limestones in the Vale of 
Clwyd, and the barren Sandstones above Pentrevoelas. 
4. MERIONETH—Slates of the Cambrian formation, the 
barren Grits above Harlech and Llanbedr, the Volcanic Rocks 
of the Cader Idris district, &c. 
In the above districts the dependence of the configuration of the 
Country on its Geology was shown by means of lantern slides; some 
analyses of rocks were also shown, and lists of the characteristic plants 
of the various localities given. ‘ 
IV.—In conclusion it was urged that lists of plants found within arbitrary 
Geographical limits—such as County boundaries—had no scientific 
interest or value. On the other hand, all attempts to trace the 
causes of the present distribution of our Flora are of the greatest 
value to Geographical Botany. Watson in his Cybele has done 
admirable work for ‘County Botany,’”-—we now want to advance 
beyond the lines laid down by him, North Wales is an admirable 
district for this kind of study, but the work cannot be done without 
co-operation. It was strongly urged that it was the duty of the 
Botanists of the Chester Society of Natural History, and of those 
connected with the University College of North Wales, to initiate 
this work, Botanists wishing to exchange ideas on this subject might 
correspond with the Chairman of the Botanical Section of this 
Society (Mr. J. D. Siddall), or with the Lecturer (Mr. J. Lloyd 
Williams, University College, Bangor.) 

