58 



THOMAS 8TEEEY HUNT ON A NATUEAL SYSTEM IN 



tical Tocks the feldsptithic element may be represented by two associated feldspars of the 

 same'geniis, — in one case ajjparently, auorthite and albite ; iu another, labradorite and 

 andésite. The diabase which along the Atlantic border of North America is found 

 irrupted among mesozoic strata, from Nova Scotia to North Carolina, is singularly uniform 

 in chemical composition and in density, and by many observers has been found to be 



VIII. 



Tribe 1. Frotoperspathoid. 



Species. 



Melilite. - - 

 Eudialyte. 



Wohlerite- - - 

 Humboldtilitc. 



Ilvaite. - - - 



Gehlenite. - - 



Sarcolite - - 



Milarite. - - 



Barylite. - - 



Meionite. - - 

 Wernerite. 



Ekebergite. - 

 Mizzonite. 



Dipyre. - - - 



Marialite. - - 



Sodalite. - - 



Nosite. - - - 



Hauyne. - - 



Lapis lazuli. - 



Leucite. - - 



Hyalophane. - 



Orthoclase. - 

 Microcline. 



Nephelite. - - 



Paranthite. - 



Eucryptite. - 



Anorthite. - - 

 BaKowite. 



Labradorite. - 



Andésite. - - 

 Oligoclase. 



Albite. - - - 



lolite. - - - 



Petal ite. - - 



Formula. 



(ca2jn,si3)Oo - (m = al|fiJ) - - 

 (m4zr2sii;)Oi8 - (m=nai.5cai.5fei.o) 

 (m3zr2sii)Oio - (m=nao.6ca2.jfeo.2) 



(ca3al.,sii)oio 



(11136,813)010 - (m = fejcaj) - - 

 (cai.omj.osii.3)o3;i - {m = al|flj) 



(caialiSi„)oj 



(m,al,si8)ojo - (m = cao.8ko-2) " 



{ba2al3si,)0j2 



(ca,alasii2)025 - ------ 



(m^alasiijosg - ------ 



(m4ali,sii8)03i 



(mjalaSiaOOa^ 



(m.,alsPi24)03, - 



(raialasi3i;)0j3 



(na4al9sii2)024cli 



(naial5si4)03 + Jna,Si04 - - - 

 (na.aLsi,)o, + |ca,s,o., - - - 



(kialjSislOi; ------- 



mialjsyoi, - (m=baJk^) - - 



(kial3si,2)Oic 



(kial3sii,)0ic 



(naial3Si.j.5)08.5 



(caial3sii)08 



(Iiial3si4)08 - 



(caial3si4)08 



(caial38i5)o.j ------- 



(inial3sic)o,o - (m = ca|nai) - 

 (mial3sia)Oi2 - (m = cajnaj) - 

 (mial3sia)o,3 - (m = naf ca}) - 



(uaial3sii2)o,i; 



(inial3si5)03 - (m = mgffej) - 

 (liiaU8i2o)o25 



19-96 



D 



6-44 



6-05 

 6-15 

 6.52 

 6-40 

 6-50 

 6-38 

 6-49 

 6-44 



G-57 



6-44 



8-42 

 8-25 

 8-62 



7-09 

 6-92 

 9-83 

 6-83 

 6-66 

 6-32 

 5-95 

 6-32 

 6-27 

 6-32 

 C-23 

 6.26 

 6-24 

 6-31 

 6-33 



Ckys. 



Tetrag. 



Rhombo. 



Clinorh. 



Tetrag. 



Orthorh. 



Tetrag. 



Tetrag. 



Orthorh. 



Tetrag. 



Tetrag. 



Tetrag. 



Tetrag. 



Tetrag. 



Tetrag. 



Isomet. 



Isomet. 



Isomet. 



Isomet. 



Isomet. 



Clinorh. 



Clinorh. 



Anisom. 



Hexag. 



Tetrag. 



Hexag. 



Anisom. 



? 



Anisom. 



Anisom. 



Anisom. 



Anisom. 



Hexag. 



Clinorh. 



Remarks. 



Chlorosilicate. 

 Niobosilicate. 



Chlorosilicates 



- with lime and 



alkalies, § 76. 



J 



Chlorosilicate. 

 Sulphatosilicate. 

 Sulphatosilicate. 

 Sulphosilicate. 



essentially an admixture of pyroxene, magnetite, and a triclinic feldspar which has been 

 represented as labradorite, and with which the composition of the rock as a whole 

 accords.' Hawes, however, observed that this diabase as found at West Rock, New Haven, 



' See Dana, Amer. Jour. Science, vi. 194. 



