178 THE ROYAL SOCIETY OF CANADA 



to the green material which is largely pyroxene with a little 

 orthoclase. 



Plate II, Fig. 4 shows slightly more advanced stage, the host is 

 reduced to narrow bands between the large crystals. The zonal growth 

 of the crystals can be detected in the photograph. 



Plate III, Fig. 5 is all garnet except the small interstices between 

 crystals. The large crystal on the left of the photograph shows a core 

 of granodiorite. The final stage is solid massive garnet in which 

 nothing of the host is left, even the nuclei of crystals having been trans- 

 formed to garnet. As such material is homogenous, it shows nothing 

 of interest in a photograph. 



In color the garnet varies from greenish, in the small crystals 

 sparsely scattered through the granodiorite, to yellowish-brown and 

 red. In one case, where garnet is accompanied by pyrrhotite, the 

 garnet is white, suggesting that the iron was taken up by the sulphide. 



Under the microscope, the garnet shows its ordinary characters. 

 The zonal structure so noticeable in the hand specimens is still more 

 pronounced. The granodiorite cores are generally considerably al- 

 tered, generally to kaolin and epidote with a little orthoclase but some 

 of the minerals, especially the accessories, remain intact. 



In the following table, two analyses of granodiorite from other 

 localities are given for purposes of comparison. The Pass Creek 

 granodiorite (Analysis 3), is that shown in Plate 1, from the edge of a 

 garnet mass on the Iron Chancellor claim. The garnet analyzed 

 (Analysis 4), was taken from the specimen shown in Plate 3, a few 

 feet from the granodiorite of Analysis 3. 



