Fig. 121. — Isle of May. One of the pools on an exposed part of the island near the lighthouse. A dwarf 
form of Heleocharis palustris, with which H. uniglumis is mixed, overgrows the entire area of the pool. 
j Proc. Roy. Socy. of Edin.] 
- ■ j ■■ - ■■ 
Fig. 122. — Isle of May. Precipitous cliff on the west of the island, consisting of black columnar basalt. 
The cliff is inhabited by great numbers of sea-birds, whose nests are placed chiefly upon the exposed 
ends of the columns, the black rock being whitened by the droppings from the birds. It is nearly 
low water, and the light zone at the base of the cliff is caused by the abundance of Balanidse, etc. 
Mr George West. [Plate 61 . — Referred to on pages 173 to 177. 
