ELIZABETHTOWN AND PORT HENRY QUADRANGLES 33 



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Quartz 8.64 1.56 1.62 2.4 S 



Orthoclase 5-56 7 .2Z 5-004 5-56 7-5 



Plagioclase 81.322 82.2 84.186 91.57 61.7 



Magnetite .464 .93 i .856 .464 2.4 



Kaolin 2 . 58 3 . 87 2 . 58 



Excess ALO3 1. 122 



Water .09 .11 .15 



Garnet ii.75 



Diopside. Hypersth 4.3 * 4.616 3.224 11. 



Light colored min 99-234 93-97 93-39 97-14 74-2 



Dark colored min.... .464 5.23 6.572 3.688 25.15 



Plagioclase Abi Ani.7 Abi An-..* Abi Ans Abi Ana.i Abi An2.4 



1 Chateau Richer, Quebec. T. S. Hunt. Geol. Sur. Can. 1863. 



2 Keene valley. A. R. Leeds. N. Y. State Mus. 30th An. Rep't. 1878. 

 p. 92. 



3 Summit of Mt Marc.v. A. R. Leeds. N. Y. State Mus. 30th An. Rep't. 

 1878. p. 92. 



4 Nain. Labrador. A. Wichmann, Zeitschr. d.d. Geol. Gesellsch. 1884. 

 36:491. 



5 Carnes Quarry, Altona, Clinton co. E. W. Morley for H. P. Gushing. 

 N. Y. State Geol. 19th An. Rep't. 1901. p. 58. 



In the quantitative system the first four analyses belong in class 

 I, Persalane, order 5, Perfelic, Canadare. No. i is in rang 3, Alka- 

 licahc, subrang 5 Persodic. Nos. 2, 3 and 4 are under rang 4, 

 Docalcic Labradorase, subrang 3, Persodic, Labradorose. No. 5 

 belongs in class II, Dosalane, order 5, Perfelic Germanare, rang 4, 

 Docalcic, Hessase, subrang 3, Persodic, Plessose. 



Of the five analyses the first four are characteristic anorthosites 

 but the last marks a transition to the gabbros proper. The larger 

 percentages of ferrous iron and magnesia are the indication of 

 this and are of course the result of increasing amounts of the 

 pyroxenic component. 



In recasting the analyses some important assumptions were 

 necessary, which do not materially change the results. Thus when 

 water was not determined in parts above and below no C. it was 

 arbitrarily divided into combined and absorbed. FcoOg, which in 

 nos. I and 4 includes some FeO, was broken up so as to give 

 magnetite. In no. i after the best possible combination of oxids, 

 1. 122 AUO. remained, and in no. 3, the SiO, failed to satisfy its 

 natural associates by 2.40. There were probably some slight errors 

 in determinations, for there seems no escape from the mineral- 

 ogical compositions used. In no. 5 the most basic one and obviously 

 well over toward the gabbros, the recast values are taken from 

 results given by Professor Gushing and involve no kaolin. 



