TAB. LXVII. 



CALX sulphata*. 

 Crystallized Sulphate of Lime, or Gypsum. 



Class 2. Earths. Order 1. Homogeneous. 

 Gen. 3. Lime. Spec. 6. Sulphate of Lime. 



Spec. Char. Lime combined with sulphuric acid. 

 Syn. Broad foliated Gypsum. Kirw.v. 1. 123. 



Gips et Fraveneis. Emmerl. v. 1. 527. 540. 



Chaux sulfate trapezienne. CEP. Haicy,v. 2. 270. 



Natrum selenites. Linn. Syst. Nat. v. 3. 91. 



Shotover Hill, Oxfordshire, seems to afford the clearest 

 and cleanest specimens of crystallized gypsum in the great- 

 est variety : yet we find some varieties are rather local, as 

 shall be shown hereafter. They are mostly found in a clayey 

 gangue. The upper figure is what Haiiy calls trapezienne. 

 Although this would by extending the lateral faces, which 

 might be easily done by piling plates on the summit, each 

 smaller than the last, form an octaedron ; yet of a great many 

 varieties which we have seen we have not observed this mo- 

 dification. The middle figure shows a very frequent variety 

 from the same place, heightening towards an octaedron; 

 but seldom extending much further than this figure. They 

 often have their angles a little irregular, so as not to meet : 

 see the left hand corner near figures 1 and 2, also having 

 other crystals sticking in them in different directions. If 



* The specific name at tab. 21. should be read Calx sulphata, and not sulphurate. 



