SS6 Mr Dunnes Deffcripttmi of an Improved Air^Pump. 



durmg' their sliutting ; but even this small addition I consider 

 wholly unnecessary. 



Fig. 4. is a perspective view of the one I made for Mr I.ees, 

 which is the best method of fitting them up; but the principle is 

 alike applicable to table air-pumps. 



Remarks upon the Wasting Effects of the Sea on the shore of 

 Cheshire^ between the rivers Mersey and Dee *. By Robert 

 Stevenson, Esq. Civil-Engineer, F. R. S. E., M. W. S., &c. 

 Communicated by the Author. 



kJN a former occasion, I had the honour to make a few obseri ' 

 vations, which appeared in the 2d volume of the Society's Me- 

 moirs, regarding the encroachment of the sea upon the land ge- 

 nerally. The present notice refers cmly to that portion of the 

 coast which lies between the rivers Mersey and Dee, extending 

 to about seven miles. To this quarter my attention, with that 

 of Mr Nimmo, Civil Engineer, had been professionally directed 

 in the course of last month. In our perambulatory survey we 

 were accompanied by Sir John Tobin, and William Laird, Esq. 

 of Liverpool, along the Cheshire shore, and its connecting sand 

 banks, between Wallasea Pool, in the Mersey, and Dalpool, in 

 the river Dee. Within these estuaries, the sliores may be de- 

 scribed as abrupt, consisting of red clay and marl, containing 

 many land or boulder stones, of the cubic contents of several 

 tons, and very many of much smaller size, diminishing to 

 coarse gravel. But the foreland, or northern shore, between 

 these rivers, 'which I am now to notice, is chiefly low ground, 

 and, to a great extent, is under the level of the highest tides. 

 The beach, or ebb, extends from 300 to 400 yards seaward^ 

 and, toward low-water-mark, exposes a section of red clay; * 

 but, toward high water, it consists of bluish coloured marl, 

 with peat or moss overlaid by sand. This beach, at about 

 half-tide level, presents a curious and highly interesting spec- 

 tacle of the remains of a submarine forest. The numerous 

 roots of trees, which have not been washed away by the sea, or 

 carried off by the neighbouring inhabitants for firewood, are in 

 a very decayed state. The trees seem to have been cut off 

 • Read before the Wernerian Society, 8th March 1828. 



