WIGTOWNSHIRE AND ITS INLAND MOLLUSCAN FAUNA 253 



WIGTOWNSHIRE AND ITS INLAND MOLLUSCAN 



FAUNA. 



By W. Denison Roebuck, M.Sc, F.L.S. 



The County of Wigtown or Shire of Galloway, with its 

 characteristic hammer-head outline facing the north-east 

 coast of Ireland across 21-^? miles of sea, and exposed to the 

 influence of the warmth of the Gulf Stream, has for its 

 distinctive feature its deeply indented and extensive coast 

 line, more than 130 miles in extent, so that no part of the 

 county is more than 13 miles from the nearest sea, and 

 only a small portion is anything like so far. Physically, the 

 county is divisible into three areas : — (i) The Moors, which 

 cover a large tract of the north ; (2) the Machars, comprising 

 the low-lying cultivated lands of the south ; and (3) the 

 Rhinns, which contain all the peninsular tract lying west 

 of Loch Ryan and Luce Bay, or west of the isthmus between 

 Stranraer and Glenluce. The county does not attain to an 

 elevation of more than 1000 feet, on the Ayrshire border, 

 the hills of Benbrake and Craigairie. There are numerous 

 freshwater lochs, none of great size, and the chief rivers are 

 the Cree, Bladenoch, Luce, and Tarf The area of the 

 county is 311,984 acres, of which in 1912 115,727 were 

 mountain and heath land used for grazing, 42,709 permanent 

 grass, 113,171 arable land, and 8526 woods and plantations. 

 The geological structure is very simple, consisting entirely 

 of Silurian rock, almost the earliest of the stratified rocks, 

 with small outcrops of trap or granite here and there ; the 

 only variation of any consequence being a narrow belt of 

 new red sandstone running along the western shore of 

 Loch Ryan. As regards faunistic habitats, there are the 

 mudflats and merse lands of Wigtown Bay, the far-reaching 

 sands of Luce with the considerable stretches of sandhills 

 known as the Torrs, the hilly moorlands and wet flats 

 known as " flows," the numerous lochs and pools, the arable 

 lands and rough pastures, the woods, and the cliffs and 

 pebbly beaches — all tending to form a region which, if properly 



