48 THOMAS STEllRY HUNT ON A NATURAL SYSTEM IN 



ÏKiBE 4. PiîoTaPHYLi.oiD. Theniiophyllite, Marmolite, Talc. (Table V.) 



Tkibe 5. OrarroiD. Serpentine, Eetiiialite, Dcweylite, Geuthite, Aphrodite, Cerolite, Clirysoiolla, Spadaite, Rens- 



selaerite, Sepinlite, Glaucoiiite. (Table VI.) 

 TniiiH C. Zeolitoid. Xantbortliite, Prebnite, Hamelitc, Catapleiiti-, the various Zeolites; with Canerinito and 



Ittnerite, Edingtonite, Sloanite, Forestite. (Table VII.) 

 Tribe 7. rKOTOi'ERsi'.\THoiD. Melilite, Eudialyte, WGhlerite, Huniboldtilite, llvaito, Gelilenite, Sarcolite, Milarite, 



Barylite, Meionite with Marialite and intermediate Scapolites, Sodalite, Nosite, Hanyne, Lapis-lazuli, 



Leticlte, Hyalophane, Orthoclase, Microcline, Nei)helite, Parantliite, Eucryptite, Anorthite, Albite and 



intermediate Feldspars, lolite, Petalite. (Table VIII.) 

 Thiue 8. I'ROTOi'BR.iDAMANTOiD. Pargasite, Keilhauite, Idocrase, Schorlomite, Garnet, -Egirite, Alhinite, Beryl, 



Euclase, Arfvcdsonite, Ardennite, Axinite, Epidote, Zoisite, Jadeite, Acmite, Spodumene, Sai>phirine, 



Stanrolite; and tlie Tourmalines, including Coronite, Sehorlite, Aphrizite, Indicolite, Eubellite, 



(Table IX.) 

 Tribe 9. PnoTopERriivLLOin. Astrophyllite, Phlogopite, Pyrosclerite, Penniuite, Ripidolite, Prochlorito, Leuchten- 



bergite, Venerite, Corundopliilite, Biotite, Voigtite, Cryophyllite, Seybertite, Thuringite, Jefferisite, 



Annite, Willccixite, Ghloritoid, Lepidomelane, Zinnwalditx?, Oellaeherite, Lepidolite, Margarite, Euphyl- 



lite, Cookeits, Damciurite, Paragonite, Muscovite. (Table X.) 

 Tkii:e 10. PiNiToiD. .Jollyte, Fahlunite, Esmarkite, Bravaisite, Hygroi)hilite, Pinite, Cossaite; with Palagonite, 



Tacliylite, Pitchstone and Obsidian. (Table XI.) 

 Tribe 11. Hydroperspathoid. No sjiecies known except perhaps Westanite. 

 Tribe 12. Perspathoid. Xo species known to represent this tribe. 

 Tribe 13. Peeadajia.ntoid. Dumortierite, Topaz, Andalusite, Fibrolitc, Cyanite, Bucholzite, Xenolile, Worthite, 



Lyncurite, Malacone, Zircon, Auerbaehite, Anthosiderite. (Table XII.) 

 THiiiB 14. Peepiiylloid. Pliolerite, Talcosite, Kaolinite, Pyrophyllite. (Table XIII.) 

 Tribe 1.5. Aegilloid. Schrutterite, CoUyrite, Allophane, Samoite, Halloysitc, Kaolin, Keramite, Wolclionskoite, 



Montmorillonite, Chloropal, Cimolite, Smectite. (Table XIV.) 



Tribe 1.— Pectolitoid. 



i) 5*7. We notice first in this tribe those hydrated silicates of lime, often with alkalies, 

 some of which are frequently found among the secretions of basic rocks, and which 

 include pectolite, xonaltite, gyrolite, plombierite, datolite, okenite and apophyllite. The 

 name selected for the tribe recalls at the same time the most common of these species, and 

 also the property which belongs to most of them of pectising or being decomposed by 

 strong acids, such as chlorhydric, with the separation of gelatinous silica. It has also the 

 advantage of distinguishing them from the zeolitoids, the corresponding type in the next 

 suborder, with which they are generally associated and sometimes confounded. Differing 

 considerably in the proportion of combined water, the pectolitoids have a hardness below 

 that of quartz and, with but few exceptions, a comparatively large atomic volume. In 

 the case of apophyllite a little fluorine is present, and in datolite a large amount of boric 

 oxyd, which in our atomic formula is represented as replacing a portion of silica. They 

 are all native species, some of which have been artificially formed, and at least one of 

 them, apophyllite, is found of recent origin in the channels of the thermal waters of 

 Plombières, in France, where another si)ecies, plombierite, has alone been met with. An 

 unnamed pectolitoid was got by Daubrée as a product of the action of superheated water 

 on glass. Belonging to this same tribe are : the zinc-silicate, calamine ; the rare species, 

 thorite and cerite ; the two maugauesian silicates, friedelite and hydrorhodonite, with 

 pyrosmalite, a ferro-manganesian species containing chlorine ; and the copper-silicate, 

 dioptase. The composition of tritomite is not certain, l)ut approaches that of cerite. Here, 

 also, mosandrite probably belongs. 



