94 
The Irish Naturalist. 
June, 
of fresh mineral particles. In both cases the part played by the living 
plants is that of binders or stabilisers. Each succeeding stage in this 
upward extension is overflowed by fewer tides than the preceding one. 
In consequence each stage is, on the whole, characterised by different 
species of plants, such as Marsh Samphire, Sea Pink, and various Grasses. 
Thus in the marshes chiefly dealt with in the lecture, i.e., those of the 
Dovey Estuary in Cardiganshire, live distinct altitudinal zones of vegetation 
can be distinguished. The lower zones are occupied by plants able to 
endure longer and more frequent submergence in salt water than those 
living in the higher and drier zones. In many localities the vegetation 
covering the greater part of the marshes is a compact sward. This 
affords excellent sheep pasturage, highly valued by farmers not only on 
account of its feeding properties but also because of its freedom from 
the liver-fluke parasite. The sward is intersected by numerous natural 
drainage channels and curious bare drainage hollows known as " pans." 
The origin and fate of both channels and " pans " was described, and 
it was shown that, as in the analogous case of sand dunes, there is a 
constant struggle between the agents of deposition and stabilisation on 
the one hand, and the agents of erosion and destruction on the other. 
Tides not only deposit additional sediment but also erode and wear away 
the edges of the marsh, and scour out and enlarge the " pans." Indeed, 
large " compound pans " are frequently formed by the coalescence of 
systems of smaller ones. Sooner or later, however, if the chief river 
currents and channels remain constant, a kind of balance is struck, the 
marsh reforming as rapidly as it is destroyed. It may also be stated 
that while some of the bare " pans " increase in size by erosion others 
become filled up and overgrown by vegetation owing to the establishment 
of natural drainage outlets. By suitable methods of encouraging the 
deposition of silt and the growth of salt marsh plants upon it, it is possible 
to so favour the forces of progression (as opposed to those of retrogression) 
that land reclamation can be effected. This is regularly carried out on 
a considerable scale in such areas as the Wash of the east of England. 
The lecture was illustrated by a large number of lantern slides from 
photos, mainly taken by the lecturer. In the discussion which 
followed, the following members took part : — The President, Rev. C. H. 
Waddell, Dr. J. K. Charlesworth, J. E. Hamilton and A. McI. 
Cleland. Professor Yapp replied to the questions asked by these 
speakers. After the election of ^liss Gibb and Miss S. Lees to member- 
ship the proceedings concluded. 
February 15. — John M. Dickson presided. Charles Bulla gave 
a paper on " Ancient Man and the Implements he used." 
The lecturer illustrated his subject witli a large number of specimens 
of flint implements of various ages, as being connected with the presence 
of ancient man — as tools for fashioning, and as implements for the 
chase, defence or offence. Through the courtesy of Mr. Deane of the 
Municipal Museum some cases of implements and a series of lantern 
slides were shown by A. R. Hogg, 
