OF EARTHS, 



39 



Thefe ftony faponaceous earths being fomewhat of a talcy 

 conftitution, are claflcd by Linnteus, and others, among talcy fof- 

 fils ; but the juflly celebrated Da Cofta, and Dr. Hill, have referred 

 them to the clafs of clays, as having on trial all the properties 

 of an indurated clay. 



It is faid this beautiful fpecics of clays enters into the compo- 

 fition of the porcelain made at Worcefter ; of the art of making 

 which, and the true fubftances ufed for that purpofe by the Cbi- 

 nefe, we have an excellent and curious account by Monfteur de 

 Reaumer (c). 



On the mores of our alpine brooks and rivers we often find a 

 fpecies of this foffil fo remarkably lapidefcent, and fo elegantly 

 variegated, as to carry the appearance of a marble. It is called 

 by fome of our common people Clay-marble. It is the Morochtus of 

 authors (d) ; of which I have met with feveral varieties. 



iy?. Of a fky-colour, elegantly clouded with a light and deep 

 red, with an arborefcent delineation like the trunk of a tree, and 

 a figure fomewhat like a bird at the top of it, in the attitude of 

 taking wing. From the fhore of the brook at G of ton. 



<ndly. Of a grey and red colour, in lighter and deeper mades, 

 with bluim-black f-pots and Dentrit, and the figure of an animal, 

 refembling a pig, in the attitude of fwimming. 



(c) Hift. et Mem. de 1'Acad. Roy. des Sciences pour 1727. 



(d) Morochtus. In Germania, et Angjia, reperitur. Charlet. Foff. p. 30. n. 14. 

 Steatites tertia. Da Cofta. Hift. FofT p. 40. n. 16. 



Morochtus, Schmeerftein Germ. Bruckm. Magn. Dei in Loc. fubter. Vol. i. p. 84, 

 and 87. 



Morettum album re&ius Porcellana nativa. Bruckm. Epift. Cent. ii. Ep. 100. p. 1244. 

 n. 10. et feq. 



$ai y , of 



