HARDWICKE'S SCIENCE-GOSSIP. 



77 



winds in driving the lighter particles of sand shore- 

 wards. 



In Weston Bay at low water the tide recedes for 

 three miles, leaving an immense area of mud exposed. 

 This is seen to be furrowed by the receding tides, 

 channels of drainage in which much of the finer 

 sediment is carried off. At times the mud appears to 

 gain upon the sand, at others the sand upon the mud. 

 In rough weather more sediment of all kinds is 

 deposited, in fine weather the finer sediments are 

 carried away, and in all weathers powerful tidal 

 currents disturb the muds, and alter and sift the 

 sediments. 



The sandy beach is, I think, in the main formed by 

 waves acting upon already deposited sediments. 

 Every wave as it breaks pounds the beach, and the 

 undertow carries away the finer and lighter material, 

 leaving the coarser and heavier behind. The former 

 is redeposited as muds of varying degrees of fineness, 

 the fineness beiDg greatest at the greatest distance 

 from the shore, the latter is left to form the beach 

 of sand, the finer particles of which are driven by the 

 winds inward to form the tots. Dig below the sand 

 and you will find clay, over mud, and therefore more 

 remote from a former shore. Dig when you will in 

 the alluvium, and if you dig deep enough for a few 

 miles inland, you will find clay, a tolerably easy and 

 convincing proof that the flat area between Cundon 

 and Worle, and again between Worle and Banwell, 

 was formed by the slow deposit of estuarine and 

 marine sediments, that the land now cultivated was 

 a muddy shore with probably an enormous tidal 

 range, and that the process now seen to be goiDg on 

 in the formation of the tots has been going on for an 

 incalculable period of time, and it may be assumed 

 that they have not yet reached their maximum. 



If a glance be taken at any ordinary map exhibiting 

 the coast-line of Somersetshire (see sketch-map 

 appended) between Clevedon and Stolford, the extent 

 of alluvium (or soil deposited as the estuary has been 

 gradually silted up) may be approximately measured 

 by the extent of the moors and their number. Be- 

 ginning at the north we have Nailsea Moor, and 

 Kenn Moor, in which is the hamlet of Seymour (a 

 common place and surname in Somersetshire, mean- 

 ing most probably sea-moor) ; between the next two 

 mountain limestone ridges, Locking and Weston 

 moors ; and between the Mendips and the Polden 

 Hills, an extensive moor, bearing locally different 

 names, as Glastonbury Moor, Godney Moor, Mark 

 Moor, etc. Altogether the area of alluvium, or land 

 gained from the sea, as silt has been deposited and 

 the tidal waters have receded, may be stated at about 

 fifty square miles. In many places in this district 

 peat overlies the clay to a thickness of several feet ; 

 but what evidence of blown sand there may be in 

 that area I am at present unable to state. Its com- 

 parative scarcity or absence inland must of course be 

 attributed to the configuration of the land and the 



nature of its formation. As the bays gradually 

 silted up, it is tolerably certain that the process 

 began along the flanks of the bounding E. and W. 

 limestone ridges ; and as the sediment accumulated, 

 the sides would expand and present a greater area to 

 the prevailing winds, and thus favour the gradual 

 accumulation of the ridges of sand which now form 

 such a striking feature in the shore scenery of the 

 Severn Estuary on the Somersetshire or eastern side. 

 No doubt cultivation has obliterated some traces of 

 inland sand ; but as the tides recede and the bays get 

 silted up, the sand-tots will grow seawards, as they 

 have already done and are doing at the present time 

 where the conditions are favourable. 



T. Stock. 



CONTRIBUTIONS TOWARDS A LIST OF 

 THE MOLLUSCA OF HEREFORDSHIRE. 



HEREFORDSHIRE is but a little known 

 county, and so it is little to be wondered at 

 that there is no list of its mollusca, even moderately 

 complete. Not that the following list is meant to be 

 complete by any means, but I trust that it will serve 

 as a basis for further records, and also interest some 

 of your readers who pay attention to the distribution 

 of British mollusca. 



Messrs. Taylor and Roebuck's list (as given in Mr. 

 Williams' smaller work) comprises only thirty-six 

 species, most of them, curiously enough, being the 

 rarer ones, e.g., Helix . fusca, Clausilia lamina/a, 

 while one, i.e., Helix Cantiana, I have not yet found 

 at all : it also excludes many of our commonest and 

 most widely distributed species, e.g., Succinea pulris, 

 Spharium corneum : so far, that is in the last two 

 years, I have, with the invaluable aid of Mr. E. W. 

 Bowell increased the list to eighty-seven species. The 

 slugs I have not yet studied particularly, but I hope 

 to do so in future, and many species are recorded in 

 the list above referred to. Of course, I have not yet 

 worked nearly the whole of the county, and no doubt 

 many new species will be added by further search. 



[Those marked (*) are recorded by Messrs. Taylor 

 and Roebuck.] 



Sph&rium corneum. Very common. " 



Sph. rivicola. Not common and small. The Lugg 

 at Mordiford, the Wye at Symond's Yat. 



Sph. lacustrc. Formerly very common in the 

 Hereford and Gloucester Canal, which is now, un- 

 fortunately, drained, for the most part at any rate. 



Pisidium fcmtinalc. Abundant where it occurs : 

 Tupsley : near Leominster. 



* Pisidium pusillum. Common. 



Pisidium roseum. Rare : but abundant near Stoke 

 Edith. 



Unio tztmidus. Fairly common. The Wye speci- 

 mens are small. Abundant, very fine and large in 

 the Canal. 



Unio pictorum. A few specimens in the Wye. 



