1022 The American Naturalist. [December, 
Backstrom” fused feldspathic phonolite and obtained as the product 
upon cooling a colorless glass filled with microlites of oligioclase, 
nepheline, small microlites of colorless pyroxene and tiny grains of 
picotite and olivine (?). Upon fusing a leucite phonolite, containing 
nosean, SO, is driven off and the resulting product is a glass enclosing 
microlites of oligoclase, a few prisms of nepheline and abundant crys- 
tals of a yellow pyroxene with the properties of aegerine. 
1 Bull. d. 1. Soc. Franc. d. Min., 1893, xvi, p. 130. 
