160 J. V.Lewis — Palisade Diabase of New Jersey. 



Analyses of Augite from the Palisade Diabase. 

 I. 



Si0 2 47-72 



Al o 3 3-44 



Fe 2 3 5-93 



FeO 18-34 



MgO 12-89 



CaO 11-40 



.... 0-SG 



Na 2 



K 2 0_. 

 MnO . 



Ign._ . 

 Insol. . 



0-37 



n. d. 



0-00 



II. 



III. 



IV. 



48-54 



50-71 



47-10 



5-50 



3-55 



4'55 



2-77 



n. d. 



n. d. 



21-25 



15-30 



1520 



7-67 



13-63 



18-65 



10-97 



13-35 



11-33 



3-10 



d. d. 



0-82 



1-48 1 



0-81 

 1-17 



n. d. 



0-17 

 1-33 

 0-34 



100-95 100-62 100-00 98*67 



1 By difference. 



I. Rocky Hill, N. J. Quarry near the middle of the trap 

 sln-et. A H. Phillips, analyst. 



II. Rocky Hill, N. J. Old quarry near the railroad station, 

 about 420 feet from the upper contact. A. H. Phillips, analyst. 



III. West Rock, New Haven, Conn. G. W. Hawes, analyst. 



IV. Aakeroe, Sweden. Partial analysis of diallage by H. von 

 Post. * 



With the exception of small deficiencies in silica in I, II, 

 and IV, these analyses correspond to the following pyroxene 

 molecnles in the proportions indicated : 



Acmite, NaFe(Si0 3 ) 2 = ac. 



Hypersthene, (Ms:,Fe)Si0 8 = by. 



Diopside, Ca(Mg>e)(SiO,) 9 -~ di. 



Aluminous molecule, (Mg,Fe)(Al,Fe) 2 Si0 6 = aim. 



IT. 



III. 



IV. 



ac. 



hy. 



di. 



aim. 



108 



: 640 



: 816 



159 



1 



: 5 93 



: 7:56 



: -1-47 



2 



: 12 



15 



3 



270 



530 



784 



- 81 



3 33 



6-54 



9-68 



1 



7 



: 13 



19. 



2 



126 



: 522 



956 



69 



1-83 



: 7-72 



13-86 



1 



2 



: 8 



: 15 



1 



?t 



: 864 



: 808 



135 





6-40 



5-99 



1 





13 



: 12 



2 



(approx.) 



(approx.) 



(approx.) 



(approx.; 



These formulas indicate a quite exceptional composition for 

 augite in the great excess of ferrous iron and magnesia over 

 lime, alumina, and ferric iron. 



* Dana's System of Mineralogy, 6th ed., p. 360. 

 f Ferric iron and alkalis not determined. 



