JOURNAL 



OF THE 



WASHINGTON ACADEMY OF SCIENCES 



Vol. VII JANUARY 19, 1917 No. 2 



MINERALOGY. — M agues ioludwigite, a new mineral. 1 B. S. 

 Butler and W. T. Schaller, Geological Survey. 



Introduction. In 1912, while making a reconnaissance examina- 

 tion of the Big and Little Cottonwood districts, Utah, one of 

 the writers, B. S. Butler, collected specimens of the rather rare 

 mineral ludwigite. 2 Specimens of this mineral from the Little 

 Cottonwood district, in an undescribed collection made by J. M. 

 Boutwell, were later examined. 



During the summer of 1916 it was possible to make more 

 detailed observations of the occurrence of the mineral, and 

 chemical analysis has shown the presence of an allied mineral, 

 hitherto undescribed, for which the' name magnesioludwigite is 

 proposed. 



Locality. The largest body of ludwigite observed is at the 

 Mountain Lake mine at the head of Big Cottonwood Canyon, 

 about 1| miles south of Brighton. Ludwigite occurs in places 

 to the southwest of the Mountain Lake mine for more than half 

 a mile, nearly to Lake Catherine, and also to the east. It was 

 collected on the south side of Little Cottonwood Canyon, south- 

 east of the Michigan-Utah boarding house. It was observed 



Preliminary papei . Published with the permission of the Director of the 

 U. S. Geological Survey. 



2 Butler, B. S., and Loughlin, G. F. A reconnaissance of the Cottonwood- 

 American Fork mining region, Utah. U. S. Geol. Survey Bui!. 620, p. 201. 1915. 



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