372 COMPOSITION OF SHELL AND CORAL LANDS. 



applied extensively, and with remarkably beneficial effects, both to the 

 pasture lands and to the peaty soils that cover so large an area in this 

 remote part of Scotland. It is chiefly along the coasts that it has hith • 

 erto been extensively employed, and it is transported by sea to a dis- 

 tance of SO or 100 miles. " In the island of Barray alone, there are four 

 square miles of shells and shell sand of the finest quality and of an 

 indefinite depth" (Macdonald's Agricultural Survey of ike Hebrides, 

 p. 401.) When covered with a dressing of this shell sand the peaty 

 surface becomes covered with a sward of delicate grass — and ihe 

 border of green herbage that skirts the shores of these islands in so 

 many places is to be ascribed either to the artificial applications of 

 such dressing or to the natural action of the sea winds in strewing 

 the fine sand over them, when seasons of storm occur. 



The coast of Ireland is no less rich in such sand in many parts both 

 of its northern and southern coasts. A century and a half ago, it is 

 known to have been used for agriculture x purposes in the north of Ire- 

 land — and nearly as long ago to have >een brought over to the oppo- 

 site (Galloway) coast of Scotland w' n a view of being applied to the 

 land (Macdonald.) In the south, according to Mrs. Hall, (Mrs. Hall's 

 Ireland,) the coral sand raised in Ban try Bay alone produces £4000 

 or £5000 a-year to the boatmen who procure it and to the peasants 

 who convey it up the country. 



On the coast of France, and especially in Brittany, opposite to Corn- 

 wall, on the other side of the English channel, it is obip,ined in large 

 quantity, and is in great demand (Payen and Boussingault, Annates de 

 Chiw. et de Phys., third series, in., p. 92.) It is applied to the clay soils 

 and to marshy grass lands with much advantage, and is carried far 

 inland for this purpose. It is there called trez, and is laid on the land at 

 the rate of 10 to 15 tons per acre. On the southern coasts of France, 

 where shell sand is met with, it is known by the name of tanque or 

 taiigue. 



The shell sand of Cornwall contains from 40 to 70 per cent, of car- 

 bonate of lime, with an equally variable small admixture of animal 

 matter and of sea salt. The rest is chiefly siliceous sand. Other va- 

 rieties have a similar composition. Two specimens oHaiigue from the 

 south of France, analysed by Vitalis, and one of shell sand from the 

 island of Isla, partially examined by myself, consisted of 



Tangiie from the Shell Sand 



Sotifh of France. from Isla. 



Sand, chiefly siliceous 20-3 40 ^ 71 7 f^ cs 7 



Alumina and Oxide of Iron 4-6 4-6 \^ ' ^' ' "^^ '^^' ' 



Carbonate of Lime 66-0 47.5 28 to 34 



Phosphate of Lime ? ? 0-3 



Water, and loss". 9-1 7-9 — 



100 100 100 



3°. Coral sand is similar in its nature to the shell sand with which 

 it is often intermixed on the sea-shore. It is collected in considerable 

 quantities, however, by the aid of the drag — being torn up by the fish- 

 ermen in a living state — on the coasts of Ireland (Bantry Bay and 

 elsewhere,) and on the shores of Brittany, especially near the mouths of 

 the rivers. In this fresh s»;'ate it is preferred by the farmer, probably be- 



