O F E A R T H S. 35 



water turbo, or whilk, immerfed in it. It is unctuous, and 

 cuts through with a filming furface $ colours the hands ; difiu- 

 fes in water freely, and is very gritty. Dry, it is powdery and 

 rough. It effervefces with aquafortis. In the fire it acquires a 

 confiderable hardncfs, and a duller colour. It is little ufed as a 

 manure, for the fame reafon, probably, that the former is not ; 

 lime being had in great plenty in the neighbourhood. 



A friable grey marie, with the fame kind of iliells, is in a 

 large boggy area by a farm, called Sunnylatvs, near Wark, in Glen- 

 dale ; the flratum of a confiderable thicknefs. It is heavy, unc- 

 tuous, and ftains the hands ; difFufes freely in water, with a 

 trifling noife, and burfts into a fine powder, with hardly any 

 grittinefs, Dry, it is powdery, and crumbles between the 

 fingers. It makes a violent effervefcence with aqua fortis. In 

 the fire it crackles a little, and acquires a more brittle texture, 

 and a bluifh-grey colour. It is ufed as a manure, and is accounted 

 excellent, It has not been long difcovered. 



There is a Variety of it at Grinds^ near Norham, with the fame 

 kind of fhells. 



I am informed by my worthy friend, Henry Collingivood, of 

 Cornhill) Efq; that he has alfo a variety of it with thefe fhells on 

 his eftate at that place. 



*v 



A brownifh-red ftorty marie is in confiderable quantities at 

 Ilderton. It is heavy, and with fome difficulty diffufible in water. 

 It breaks flowly in the mouth with fome gritty particles, of a 

 harfh and naufeous tafle. Depurated, and worked into a pafte, 

 it cuts through with a glofify furface. It effervefces with aqua 

 fortis. In the fire it crackles and burils, and acquires a great 

 hardnefs, and a dull red colour. 



F 2 Thefe 



