214 GUERNSEY CLAYS. 



the other ingredients of the rock, quartz, &c., are present in 

 large proportions, but these could be removed by washing, as 

 is done in Devonshire, and good Kaolin clay produced, if it 

 would repay the labour. The section here is intersected and 

 over-arched by veins which follow the habit usual in such 

 situations, to which Mr. De La Mare drew our attention at the 

 Yrangue clay-pit. More striking examples of the same may 

 be seen at the St. Andrew's clay-pit. Here narrow veins rise 

 vertically or nearly so from the lower level, but when ap- 

 proaching the superincumbent clay or surface soil, they bend 

 over to a horizontal direction, generally agreeing with the 

 slope of the surface. These veins are rendered conspicuous 

 by their high colouring, blue or pink. I show specimens from 

 two of them at the St. Andrew's brickfield ; the rough Kaolin 

 is from one at the Yrangue ; the specimen of prepared Kaolin 

 clay, or pipe-clay, is the material imported from Devonshire 

 for use in the local manufacture of pipes. 



On our beaches, bands of clay, or broad veins filled with 

 clay, are rather numerous, the daily action of the tide hasten- 

 ing the process of decay. One such at the Longstore and 

 another at St. Sampson's Harbour are noted, the clay is highly 

 plastic, and when exposed at low tide after a gale is dug by 

 iron founders and others, and is used for stopping furnaces, 

 cracks in ovens, &c. ; this kind is locally termed " Butt clay." 

 2nd. — Clays forming true superficial deposits. 



These, as I have said before, are very widely distributed. 

 They cover the disintegrating rock and are nowhere covered 

 by the rock or intersected by the veins, which rise towards 

 the clay and turn off horizontally beneath it. These clays 

 lie in a solid compact layer of varying thickness, they show 

 scarcely any signs of bedding, angular stones can occasionally 

 be obtained from them — these are nearly always irregular and 

 sub-angular pieces of local rocks. At the base of the clay 

 lying on the rock, larger masses of stone of similar character 

 frequently occur. These clays are nearly always of a reddish 

 yellow colour; when fresh dug, especially from some depth, 

 they are sometimes blue, but turn to the normal colour after 

 exposure to the air. They vary in composition, being gene- 

 rally a clayey loam rarely plastic. The more plastic beds 

 can be seen at the Vauquiedor clay-pit, at the Naftiaux, 

 at St. Martin's, new brickfield at Cobo (near the Guet), at the 

 back of Delancey Hill, &c. Sometimes the two qualities are 

 found in the same pit, as at the Vrangue, where the clayey 

 loam nearer the surface changes into plastic clay at a greater 

 depth without any definitely marked dividing line. The term 



