229 



between tlie mnscovite-laminae. As a produot of alteration finally 

 brown-iron-ore (limonite) is found. 



Andalusitc-in/ca-scht'st. This hard, distinctly schistose, redd isli -grey 

 rock, in which the naked eye discerns only silvery muscovite-laminae, 

 was found as a bonlder only in the Wai Miha. In the thin sections 

 the rock, of which qiiai'tz forms the jirincipal constituent, shows a 

 crystalloblastic structure. Numerous are likewise colourless laminae of 

 muscovite, and besides those of a greenish mica. Andalusite is found 

 in the form of colourless prisms stringed together and in grains, 

 whilst prisms of tourmaline scarcely e\'er occur. Rutile forms dark- 

 brownish red, very strongly refractory grains and knee-shaped twins. 



Mica-quartzite-sclnst. A boulder from the Wai Kabuta, a hard, 

 grey and vei-y fine-grained, distinctly stratified rock. Under the 

 microscope we perceive that cpiartz, which is usually accompanied 

 bj' muscovite, is the chief constituent, whilst in strata of a darker 

 colour, but restricted to these, biotite is likewise freely spread. 

 JMoreover andalusite occurs in the form of aggregates of prisms, with 

 numerous ore-grains and further occasionally garnet, rutile, titanitc 

 and tourmaline. 



Mica-quartzite occurs among the boulders of the Betino, a left 

 tributary river of the Wai Miha. In this fine-grained, reddish-grey 

 rock numerous muscovite-laminae can be discerned by the naked 

 eye. As appears from fig. I the quartz individuals do not exhibit, 

 '•Pflasterstructur" under the microscope, but they engage into one 

 another like teeth. Further it must be remarked that finely distributed 



Fig. 1. 

 Proceedings Royal Acad. Amsterdam. Vol. XVlI. 



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