118 GEOLOGICAL AND MINERALOGICAL NOTES. 



thus shown to be quite distinct from any member of elaeo- 

 lite-zircon-syeiiite groiip heretofore described, inasmuch 

 as it contains hypersthene and olivine without a glassy 

 groiind-mass, and it is equally distinct from the typical 

 aiigite-syenite of Vom Rath. We, therefore, have a dis- 

 tinct variety in this Magnoliaoutcrop. Sections from the 

 I^anesville outcrop opposite Young avenue contain olivine. 

 In some of the sections Serpentine has developed in the 

 cleavage cracks and some of the feldspars have the micro- 

 scopical characters common to anorthoclase, extinguishing 

 by sections and in patches. This is the soda-microcline 

 of Professor Brögger (Zeitschrift für Krystallographie,Vol. 

 XVI, page 261). One section shows multiple twinned al- 

 bite intergrows directly across the twinned microcline, giv- 

 ing it a very beautiful appearance when seen in polarized 

 light. This form is characteristic of Professor Brögger's 

 microcline-microperthite in the augite-syeniterocks of Nor- 

 way. There are also numerous irregulär fragments of 

 8ßgirine and a few small triangulär patches of uepheline 

 with a ground-mass of quartz as a cement. 



At the augite-syenite outcrop in Brace's Cove, East 

 Gloucester, and by the roadside on the sand beach near the 

 Niles farm buildings, on the southvvest side of Eastern 

 point, the large, almost perfect tabular feldspar ciystals 

 give this rock a very striking appearance. The microscopic 

 structure of thin sections, when studied with the polarizing 

 microscope, gives the followingmineralsin its composition : 

 much augite, green hornblende, glaucophane and chlorite 

 as secondary products in the decomposition of the horn- 

 blende, microliths of segirine, one characteristic crystal of 

 hypersthene, magnetite, Hmonite, numerous zircon and 

 apatite crystals, orthoclase, microcline-microperthite, some 

 plagioclase, and a little quartz as the ground-mass. The 

 large tabular porphyritic crystals of feldspar are micro- 



