306 Proceedings of the Royal Physical Society. 



slope of fallen material, they are, as time goes on, being 

 washed and wasted into mere gravel slopes, like the obscure 

 gravel platforms of the " high-level " gravels in the south 

 of England. By the time they haVe become effaced, the 

 gradients of the rivers will perhaps have become so low, and 

 their powers so enfeebled, that we may not have others to 

 replace them. One great beauty of our valleys will then be 

 gone. N"ature will no longer put in this artful touch of the 

 artificial, until such time as the country enters upon a new 

 phase of geological activity inducing corresponding activity 

 in the streams. And so 



"From side to side eternal swerving 

 They zig-zag on. " 



XXVIII. Additional Notes on the Algce of the Firth of Forth. 

 By George Wm. Traill, Esq. [Communicated by 

 Prof. Duns.] 



(Read 21st February 1883.) 



Note of species new to the Firth of Forth, discovered 

 during the year 1882, with exhibition of specimens. 



1. Herponema vehctina, J. Ag. — Parasitical on Himanthalia 

 lorea at Pittenweem, Kilrenny, Crail, etc. (G. W. T.). 



2. Fucus distichus, Ag. — Found cast ashore at Port Seaton, 

 by Mr J. E. Henderson. Identified by Mr E. M. Holmes. 

 New to Britain. 



3. Callithamnion corymhosum. — Growing on muddy rocks 

 at Joppa. Uncovered only at very low tides (G. W. T.). 



4. Gymnogongrus Norvegicus. — Growing at Drummore, in 

 pools at very low tides (G. W. T.). 



