R. A. Farquharson — Petrology of N. Kalgoorlie. 107 



Tibia. — Owing to its imperfect state of preservation one specimen 

 obtained presents some difficulty in determination, but it is tboup;ht 

 to be the proximal end of a tibia. It belongs to the right side 

 and has both the anterior and postei'ior tuberosities damaged. It 

 is of considerable size ; the shaft is flattened posteriorly, and its 

 circumference at the break is nearly 10 cm. The width of the 

 femoral articular surface is 69 mm. in spite of the edge of the 

 external tuberosity being missing. This measurement is not quite 

 attained by any of the corresponding bones of T. grandidieri in the 

 national collection, and greatly exceeds that of the larger specimen in 

 the earlier collection from Malta. Among the casts presented by 

 Mr. Tagliuferro is that of a nearly perfect right tibia of much larger 

 proportions than any of tbe above. 



Phalanges. — The collection includes an almost perfect specimen 

 of a small terminal phalanx ; it is comparatively wide for its length, 

 measuring 16 mm. across by 27 in length. The constriction at its 

 articular end is more marked than in the specimens from Malta. 



III. — Notes ox the Petrology of a portion of the IS^orth 

 Kalgoorlie Field.' 



By E. A. Farquharson, M.A. (Oxon.), M. Sc, F.G.S., 

 Petrologist to the Mines Department of Western AustraUa. 



(PLATES V-VII.2) 



Contents. 



1. Introduction. 



2. Previous Literature. 



3. Classification of the Kocks. 



A. The Quartz-Keratophyre. 



B. Eocks of Gabbroid or Doleritic Origin. 



C. Tale-Chlorite Eocks. 



D. Eocks of Doubtful Origin. 



4. Description of the Eocks. 



5. Conclusions. 



I. Introduction. 

 rpHE majority of the numerous papers that have already been 

 I published on the petrology of Kalgoorlie have dealt with the subject 

 only in a more or less general "way. Few investigators have hitberto 

 devoted their energies to the study of one portion of the field, and 

 even Larcombe, whose main thesis^ seems to have been tbe study of 

 the Golden Mile, has chosen an area in which owing to the magnitude 

 and depth of the lode formations, and the consequent chemical and 

 thermodynamic alterations, definite clues as to the original rock types 

 could hardly be expected to remain, since there can be no doubt that 

 in -petrology, as in stratigraphy, much li<>ht can occasionally be 

 thrown on the most difficult jiortions of a field by the study of the 

 outlying ])ortion. It has therefore becTi with considerable interest 

 that the investigation of the North End has been begun, 



' By permission of the Director of the Western Australia Geological Survey. 

 - [Plates VI and VII will appear in the concluding part of this paper. — Ed.] 

 ^ Geology of Kalgoorlie. 



