r58 



NEW YORK STATE MUSEUM 



occurring in considerable amount there; and the Rand hill rock 

 furnishes still another illustration of the close parallelism of the 

 two series. 



An analysis of the anorthosite gabbro from Carne's quarry 

 has been made by Prof. E. W. Morley to whom the writer wishes 

 to express his great indebtedness. This analysis follows to- 

 gether with one of an Adirondack anorthosite and one of an Ad- 

 irondack gabbro for comparison. 



1 2 3 4 



Si 2 47.42 51.62 54.62 .8603 



A1 2 2 17.34 24.25 26.5 .2397 



Fe 2 3 4.91 1.65 .76 .0103 



FeO 10.22 5.3 .56 .0736 



MgO 5.21 1.21 .74 .0302 



CaO 8.09 9.97 9.8S .178 



Na 2 3.48 3.49 4.5 .0563 



K 2 1S9 1.27 1.23 .0135 



H 2 1.13 .72 .91 



Ti0 2 3.6 uudet. 



P 2 5 06 



ci 21 



MnO 06 .1 



BaO .04 undet. 



Total 100.06 99.78 99.70 



0=C1 05 Sp.gr. 2.8 



100.01 



1 Analysis by E. W. Morley of the least metamorphosed hy- 

 perite gabbro that I have met in the Adirondacks, Hopkinton, 

 St Lawrence co. 



2 Quartz-anorthosite-gabbro, Carne's quarry, Rand hill, Altona 

 township; analysis by E. W. Morley. 



3 Anorthosite, analysis by A. R. Leeds, 13th annual report 

 New York state museum, 1876. 



4 Molecular ratios of analysis 2. 



From the molecular ratios a rough calculation of the mineral 

 composition of the anorthosite gabbro is readily made, the al- 



