240 EDWARD B. MATHEWS 
Fine grained type.— Fine granular ; poor in perthitic feldspar, 
micropegmatite, and fluorite but bearing some muscovite. 
Emphasis has often been laid on the variations in the chemi- 
cal or mineralogical composition of masses showing uniformity 
in their texture. The present instance represents on a large 
scale the opposite changes. Here there are well-defined differ- 
ences in texture in a mass of uniform chemical composition. 
The changes in mineralogical composition are slight, and 
represent little or no difference in the chemical proportions of 
the mass except in the case of the fluorite. The other changes 
are local and partake of the nature of ‘‘dark patches.” 
Besides these original differences in the textures there are 
others of secondary origin where the feldspar phenocrysts have 
become lenticular ‘‘eyes”’ and the massive granites have been 
changed to granite-gneisses. 
Epwarp B. MATHEws. 
