22 July 1749. 



ing fine texture. There are fome grains 

 of a dark fpar fcattered in it, which, to- 

 gether with Ibme other inequalities, form 

 veins in it. The ftrata which ly upper- 

 moft in themountains confift of a grey lime- 

 ftone, which is feemingly no more than a 

 variety of the preceding. The black lime- 

 ftone is conftantly found filled with petre- 

 fadions of all. kinds, and chiefly the fol- 

 lowing : 



Peffinites, or petrefied Qftrece Petfmes. 

 Thefe petrefied fliells were more abundant 

 than any others that have been found here, 

 and fometimes whole ftrata are met with, 

 confiding merely of a quantity of fliells of 

 this fort, grown together. They are gene- 

 rally fmal], never exceeding an inch and a 

 half in length. They arc found in two 

 different ftates of petrefaclion ; one {hews 

 always the imprefiions of the elevated and 

 hollow furfaces of the fliells, without any 

 veftige of the fliells themfelves. In the 

 other appears the real fliell flicking in the 

 ftone, and by its light colour is eafily dif- 

 tinguifhable from the ftone. Both thefe 

 kinds are plentiful in the ftone; however, 

 the imprefiions are more in number than 

 the real fliells. Some of the fliells are very 

 elevated, efpecially in the middle, where 

 they form as it \vere a hump; others again 



are 



