133 



HornbleTide is not abundant, but occurs in largish, irregu- 

 lar flakes developed across the schistosity, and containing 

 inclusions of all the other minerals. 



There is a little zircon, sphene, and rutile in small cry- 

 stals and grains. 



There are a few curious pseudomorphs present. These 

 are square in cross section, and consist of a fibrous brownish 

 aggregate of radiating fibres with weak double refraction. 

 Their size is very minute, and I have not been able to deter- 

 mine the mineral. In another specimen from the same locality 

 hornblende is somewhat more abundant. 



Rocky Gully. Biofife gneiss. — In general characters 

 very like the rock described above. It has no hornblende. 

 In addition to albite and orthoclase, a small amount of 

 anorthoclase is present. Biotite is partly bleached to a light 

 bluish green material, which is almost uniaxial. This bleach- 

 ing is accompanied by the separation of brilliant golden yel- 

 low webs of "sagenite," or of beautiful little six-rayed 

 rosettes of the same material. Sometimes these rosettes are 

 arranged on an axis, the whole very strikingly resembling 

 in shape a Norfolk Island pine. There is also a good deal 

 of orange-red primary rutile present. Some of the iron ore 

 is ilmenite, and is decomposing into or intergrown with rutile. 



Rocky Gully. Pefirmafife. — Rock is coarse in grain, 

 and consists essentially of quartz and felspars. 



Quartz is in large grains of irregular shape, some of 

 which show no strain structures, though most have undu- 

 lous extinction, or are granulated. The quartz contains 

 small gas and liquid inclusions of very minute size. Felspars 

 are remarkable for their variety. Orthoclase, anorthoclase, 

 albite, and oligoclase-albite are all present, and can be dis- 

 tinctly dififerentiated. They are all rather decomposed, and 

 show a considerable amount of strain. There is a little 

 biotite present in long thin flakes, often bent and broken. 

 It is partly intergrown with muscovite, and partly decom- 

 posed into talc." 



Muscovite is very subordinate in amount. In addition 

 to that noted above, there are flakes developed as inclusions 

 in the felspars parallel to the zonary lines, indicating traces 

 of potential crystal edges. (Plate ii., fig. 1.) 



Rocky Gully. Pegmafife.-A^ery similar to the last 

 one on the whole. Felspar is more abundant than quartz, 

 and a good deal of it shows ''moiree" structure. All stashes 

 are observed, from perfectly untwinned orthoclase, through 

 orthoclase with slightly undulous extinction (obviously the 

 result of strain) to ''moiree mikroklin," and ultimately to 

 'gitter mikroklin" structure. The twinning is always so fine 



