138 



on the shore, or are broken (as they often are) on purpose 

 for examination. The larger lumps (commonly called Sep- 

 taria, and formerly Ludus Helmontii*) most generally con- 

 tain them in greatest perfection among the divisions or sort 

 of cracks in the insides. 



The upper figure is prettily relieved by the delicate yellow 

 carbonate of lime, or waxen vein, as it is commonly called, 

 which fills up the divisions, and the Lepastri are generally 

 fixed on the calcareous partitions, which are often crystal- 

 lized, varying in colour, thickness, and number of coats. 

 This specimen is remarkable for having a star on the side, 

 placed immediately on the argillaceous marie, which is re- 

 presented divided by the carbonate of lime. 



TAB. CLXXIII. 



The Lepastri vary in general form, but not much in their 

 crystallization ; that is to say, they vary in the height, 

 largeness, and spreading of the group. Thus there are four 

 the most general appearances of these aggregated stellae, 

 which are perhaps sufficiently described by the figures. It 

 may however be observed, that the ends of the crystals 

 generally incline downwards ; indeed they are rarely other- 

 wise \. 



The piece of Septarium is covered with two coats in this 

 specimen, as well as the last, but is of the more usual co- 

 lour. The coat on the left hand side appears to be just 

 forming. 



* Of which we shall speak more at large in another place, 

 f We shall explain the crystallization with some larger varieties of Sul- 

 phate of Barytes shortly. 



