236 



Van Nouhuys moreover coUeL'ted in the bed of the Wai Miha a 

 'pluiUiU'rhreccl'i consistin<>' of mimeroiis aiigiüar, sometimes a little 

 romuled fragments of phyllite having a diameter of at the utmost 

 3 em. They are usually strongly altered, and have consequently 

 given occasion to the formation of chlovitic minerals. As appears from 

 the microscopic examination the white quartz-cement is composed 

 of some grains of quartz as clear as water, the angles of which 

 engage into one another like teeth. 



In the neighbourhood of Cape Pasturi boulders were found of a 

 hard, grey, distinctly strated quartzite, containing moreover a great 

 number of small hexaedrons of pyrite. Under the microscope the 

 eye discovers, beside the grains of quartz which are as clear as 

 water, green lamellae of chlorite, little titanite and a few- black 

 grains of ore. 



For the present moment it is still impossible to determine the 

 age of the strata of phyllite. It is certain that the folding they have 

 been submitted to, has taken place before the deposit of the Jurassic 

 sediments which show nothing of this nature. Petrographically some 

 fragments are completely identical to some Cambrian rocks in the 

 Ardennes, especially those belonging to the etage devillo-revinien. 

 Much nearer to hand is a comparison with similar rocks of the 

 continent of Australia. Whilst there the Cambrian sediments ai-e 

 chietly represented by limestones, those of the Praecambriuni contain 

 not only similar rocks as those of Taliabu, but it appears that they 

 are likewise strongly folded all over the continent. 



In the strata of the Jurassic system found in Taliabu, a few rocks 

 are found which, also from a petrographical point of view, draw 

 special attention. Van Nouhuys reported already that S. E. from the 

 mouth of the Wai Najo cliffs are found consisting of "iron-hard 

 "dark rock having on ""the fracture entirely the appearance of con- 

 "glutinated gun-powder. This rock contains belemnites, which are 

 "however as a rule badly conserved, and are often cemented with 

 "the inclosing rock. Moreover the rock behaves entirely like granite, 

 "as it is split into steep perpendicular prisms divided into blocks 

 "by cross-fissures. This rock likewise changes into another of a 

 "lighter colour, in which on the weathering-planes reddish quartz- 

 "grains are found." ^) 



The rock that is meant here, is a chloritic iron-oolite (chamosite) 

 dull, of a deep blackish-green colour, and containing numerous 

 small grains, which have indeed great resemblance with gun-powder. 



1) Bijdrage tot de kennis van het eiland Tahaboe, p. 1195. 



