TABLE OP ANALYSES 



1Qt> 



1 



J. 



XL 



TIL 



1 



65.43 1 

 0.50 

 16.11 

 f 1.15 

 t 2.85 j 

 0.23 ' 

 1.49 

 0.03 

 0.40 

 5.97 

 5.00 

 0.13 



0.78*i 



j 



IV. 



V. 1 



VL 



vri. 



SiO., 



TiO, 



(>3.45 

 0.07 



18.31 

 0.42 

 3.56 



None. 

 2.93 

 0.13 

 0.35 

 5.15 

 5.06 



Trace. 

 0.30 



65.65 ' 

 '1*6. 84' 



66.60 

 0.76 

 15.05 

 1.07 

 4.42 ' 

 Trace. 

 2.21 



' * ' b'.36 

 5.42 

 4.03 



* * ' 0*41 



66.13 1 

 0.74 

 17.40 



} 2.19 1 



0.13 

 O-Sl 



59.78 



64.35 



Al,(3i 



16.36 

 f 3.08 

 I 3.72 



2.96 



15,46 



FeA 



FeO 



MnO 



}7.50 



CaO 



BaO . ... 



2.47 

 



"0.13* 

 5.04 



5.27 



i 



0.36' 



3,58 



M2O 



0.04 

 5.60 

 5.28 



"V.22' 



0.69 

 5.01 

 5.39 

 CO2 0.75 

 1.58 



0.50 



K,0 



Na.,0 



3.45 

 3.28 



P2O3 



Los« 









99.73 



99.71 



100.18 



100.33 



99.54 



99.96 



99.84 



Specific gravity of number I is 2.717 at 20*^ centigrade. 



I. Augite-syenite (akerite), Loon lake, New York. Analysis by E. lY. Morley.f 



XL Augite-syenite (akerite) from Diana, New York. Debcription and analysis 

 by C. H. Smyth, Jr., in this Bulletin, vol. vi, pp. 271-274. 



III. Syenite, mount Ascutney, Vennout. Petrographical data by Tl. A. Daly, 

 analysis by L. G. Eiikins, in U. S. Geological Survey Bulletin no. 148, p. 68. 



I Y. Akerite, Gloucester, Massachusetts. Description and analysis by H. S. Wash- 

 ington, in Journal of Geology, vol. vi, p. 798. 



V. Akerite, between Thinghoud and Fjelebua, Norway. Analysis by Mauzelius, 

 descrii>tion by Brogger, in Zeitschrift fur Ivrystallographie, vol. xvi, p. 4(), 1890. 



YI. Syenite, Silver Cliff, Colorado. Description by Whitman Cross, analysis by 

 L. G. Kakins, in 17tli Annual Report, U. S. Geological Survey, part ii, p. 281. 



YIL Banatite, Farsund, Norway. Description and analysis by Carl Fred. Kol- 

 derup, Bergens Museums Aarbog, 1896, p. 213. 



TXie Loon Lake rock (column I) is composed of microperthite, aiigite, 

 hypersthene, and quartz, with a little magnetite and oligoclase, and such 

 small amounts of apatite and zircon that they in no vi^ay affect the totals. 

 With this comparatively simple make-up it would seem an eagt}^ matter 

 to calculate the composition of the rock. It soon appears, however, that 

 the augite must be peculiar, and that a wholly satisfactory calculation 

 can not be made until it has been analyzed. It must be either very rich 

 in iron or alumina, or both, or else contain considerable alkali, but its 

 optical characters are not those of any known alkaline pyroxene. Further, 

 the available analyses of aluminous augites show that a high alumina 

 percentage usually implies a large content of ferric iron, which is mani- 



* Includes F, 0.08, 01, 0.05; FeSo, 0.07, 



fThe gieat obi jj^at ions of tlie writer to Professor Moiley tor this analysm arp giatefullyacknow I- 

 edged. 



