JASPER. 549 



The varieties which originate in clay, are fre- 

 quently characterized by a high degree of resinous 

 lustre ; and it is important to distinguish them, 

 as they have here been done, because they appear 

 to have given rise to the belief in stratified pitch- 

 stone, although essentially different in their mi- 

 neral characters, as well as in their geological 

 connexions. The greater number of the Hun- 

 garian pitchstones, (so called,) existing in the 

 cabinets of mineralogists, will be found to belong 

 to this place. 



The forms of jasper vary according to these 

 several circumstances of position. Like lime- 

 stone or serpentine, it is found in irregular masses, 

 obscurely, or not at all stratified. In other cases, 

 in the primary rocks, it appears to form true 

 strata; a circumstance to be expected. Among 

 the secondary rocks, it is massive and shapeless 

 where it passes into claystone, and is stratified 

 where it forms a portion of the series of strata 

 connected with the trap. 



As it is also found in a state of transition into 

 the ordinary stratified rocks, in both classes, it is 

 easy to conceive how it may occur in small por- 



