34 INDEX. 



H. 



Hanover* 



Tonniefberg near Wetbcrgen, and its remarkable petrifac- 

 tions, 59. 



HeUotropio. See Jafper. 



Herculaneum buried under petrified afhes or volcanic tufo, 129. 

 Hornberg. See Hornftone. 

 Hornblende, its fimilarity with fherl, 228, 

 . in oriental Bafaltes, 252. 



Horn-Jlate, a mixture of clay, quartz, and mica, entirely dif- 



folved and blended into one Ihivery fubftance, 6. 327. 

 Hornfione (Petrojilex), 



a mixture of quartz and mica, 327. 



(grey) with an impreffion of a Cornu dmmon'u, from 



Cerlgo, 27. 



the name of Hornftone erroneoufly, but very often, 

 given to flints and lilicious Hones, 327. 

 list wells, 



in a volcanic ground, in Iceland produce white pot- 



ftone and Calcedonies, 57. 



in a volcanic ground a' lagni di S. Filippo depofit a 

 fine calcareous porus, 245. See Travertine. 



Hydria. 



Mercurial mines, 8 10. 



