Apr., 1890 . 
REPORTS OF SOCIETIES. 
95 
the corolla and perianth being on one side ; Mr. Cracroft, modified 
quartz from the Crystal Mountains, America. Mr. T. H. Waller, 
B.A., B.Sc., then gave a lecture on “The Story of a Pebble.” The 
lecturer said the difficulty of the subject was to tell where to begin. 
If we visited the gravel pit in Sutton Park we should find the stones, 
when touched with the hammer, very friable. The cracks all start 
from the point where they touch some other stone, and are vertical. 
Some local and exceptional cause brought this about, possibly the 
faulting we find in the neighbourhood. We shall also find among the 
stones some cavities containing casts of stalks of Encrinites, showing 
that pebbles of mountain limestone had been dissolved by the action 
of rainwater. If we look over the loose stones we shall find pebbles 
of quartz, porphyry, tourmaline, and perhaps a few of granite, though 
these are rare, and no end of quartzites. They all give evidence of 
rapid water action, and were possibly brought by a great river from 
the north. Such deposits are now being formed in the Himalayan 
district of India. The lecturer described the mountains from which 
these fragments were possibly torn, ground down to sand, and 
cemented together again by a solution of silica which it was not diffi¬ 
cult to account for. When the sand grains were well rounded the 
rocks contained many enclosures. The lecturer concluded by wonder¬ 
ing whether our island would be elevated in the future to join the 
Continent, or depressed until the mountain tops alone were visible. 
The lecture was illustrated by a series of rock sections under the 
microscopes.— March 17th. Cryptogamic Botany. Mr. H. Hawkes 
exhibited a collection of British ferns, also a collection made by Dr. 
Arnold about fifty years ago; Mr. J. Collins, a collection of Belgian 
mosses, most of the species are found in England, though some are 
very rare; Mr. G. Corbett, lignite from Brook Point. Under the 
microscopes, Mr. Hawkes exhibited a set of twelve slides showing the 
structure and form of iEcidia; Mr. J. W. Neville, Hydrodictyon utricu- 
latim, in four stages of growth. 
OXFORD NATURAL HISTORY SOCIETY.—February 25th. 
Professor Green in the chair. In the absence of Dr. Murray, who, 
owing to recent illness and pressure of work, was unable to deliver his 
proposed lecture, Mr. Ryman Hall kindly exhibited, by oxy-hydrogen 
light, and explained a series of photographic slides of the Falls of 
Niagara, most of them taken in winter, and showing beautiful effects 
of the action of frost on the spray of the falls. He also illustrated 
with diagrams and actual photographs the construction of the Forth 
Bridge. Mr. H. M. J. Underhill commenced a series of interesting 
illustrations of the process of preparing lantern slides of microscopic 
objects; but the demonstration was unfortunately cut short by the 
failureof the gas. They will be resumed, it is hoped, on a future occasion. 
Mr. Druce showed specimens of a new variety of Agrostis. A. canina, 
var. scotica , from Ben Eay, which had been at first supposed by him 
to be the Scandinavian form Agrostis rubra. Mr. Druce expressed a 
hope that the true rubra might hereafter be found in Britain.—March 
11th. Professor Green in the chair. Professor S. Vines delivered a 
lecture on “ Some Adaptations of Plants for the Preservation of 
Chlorophyll.” This was in continuation of a previous lecture on the 
action of chlorophyll, by the absorption of light, in assisting the nutri¬ 
tion of plants. The lecturer first pointed out how the aim of the plant 
was so to use its chlorophyll as to get the greatest amount of advan¬ 
tage out of it, without undue waste by oxidation. This economy is 
aided by adaptation in two different directions: first, in the actual 
