Photomicrograph of no. 440. Canada Hill granite. Taken with plain light, magnification 

 about 30 diameters. 



Showing the typical habit of the Canada Hill type of granite: a Dominant feldspar, showing 

 plainly in the field because of slight sericitic alteration (gray grains) . b Prominent quartz (clear, 

 nearly equidimensional grains), c Biotite f.akes with prominent sagenite structure of crossing 

 rutile needles (black in this reproduction) . This rutile content and the slightly modified appearance 

 of the feldspars is a very characteristic minesral habit of the Canada Hill type. 



Plate 12 



_ Photomicrograph of no. 450-6. Canada Hill granite from Kings quarry. Taken with crossed 

 nicols, magnification about 30 diameters. 



Taken to show the distribution of feldspar and quartz constituents and the general structure 

 of the rock. The chief feldspar is microcline. Quartz occurs in small irregular grains. Biotite 

 is in oriented plates. Three crystals of garnet occur in this field (black in this light) . 



