74 
L. Beesley. 
A FOUNTAIN ALGA. 
By L. Beesi.ey, B.A. 
(Dulwich College). 
[Plate 1 and Text Figs. 74 and 75.] 
N certain of the pools in the neighbourhood of Fleam Dyke, at 
Fulhourne, in Cambridgeshire, subterranean springs make 
themselves evident as small fountains, which keep the particles of 
sand and chalk in constant movement. 
During one of the Botanical Excursions in the Long Vacation 
of 1902, my attention was directed by Professor H. Marshall Ward 
to the peculiar green colour of many of these submersed fountains, 
due to an Alga which is constantly associated with the fountains— 
and the fountains only—in a particular pond, and it was suggested 
that I should attempt the cultivation and determination of the 
Alga, since it appears to have been hitherto undescribed. 
The particular habitat of the Alga referred to above is a pond 
about 12 ft. in diameter with a general depth of 15 ins. From this 
pond a small stream flows to join a large dyke, which dyke drains 
the surrounding fields. 
Through the floor of the pond numerous small springs bubble 
up continuously, like fountains, and drive the particles of sand, etc., 
into active motion, and in the throat and neighbourhood of these 
fountains small green particles are seen which are constantly kept 
moving by the issuing current of water. In places the whole of the 
floor is covered with these green particles and being kept always in 
motion by the bubbling spring presents a most interesting and 
beautiful appearance. 
The general temperature of the water in the pond was 1 F4°C, 
while the temperature of the dyke into which it emptied was found 
to be 13'5°C. 
The green particles on examination were found to consist 
almost entirely of grains of sand and flint—of about the same size 
as ordinary sea-sand—on the surface of which the thallus of the 
Alga spreads itself as a covering. 
There are other springs to be found near these, but in none of 
them does the particular Alga appear to grow. In one of them, 
however, there are similar grains of sand on which many different 
species of Diatoms grow in great profusion and attain a very large 
size. 
