227 



Taliabii is a longituriinal island extending in the direction from 

 East-West between 124°8' and 124°4r E. and 1°50'— 2° S. Whilst 

 the length amounts to 117 km., the width is no more than 3772 

 km. A mountain range of an a\erage heigld of 1000 to 1200 m. 

 extends over its entire length. The formations of the northern part, 

 hitherto little known, are restricted to old slate-rocks, qnartzites, 

 granite-porphyry and coral limestone, whilst on the southern part 

 moreover extensiv^e strata are found containing numerous fossils 

 from the Jurassic system tliose of the Berriasien included ^). Among 

 the eruptive rocks occurs especially much gi-anite. Younger forma- 

 tions play here likewise an inferior part, because the coral limestone 

 is found oidy in the eastern half of the south-coast and no farther 

 than cape Kon a [Mantarara] ^). 



Granite. Van Nouhuys already called the attention to the fact 

 that the granites of Taliabu have much similarity with the granites 

 described by Verbkek of the Banggai Islands, which are situated 

 westward from the Sula Islands. They are characterized by the 

 occurrence of daik red orthoclase, greenish dull white plagioclase, 

 white quartz and black biotite'). Rocks in which the orthoclase is 

 of a lighter colour are however not wanting in Taliabu. They are 

 contrary to most granites of the Indian Ai-chipelago, which as a 

 rule are rich in plagioclase, to be regarded as normal biotite-granites, 

 in which a more subordinate place is assigned, to oligoclase. It 

 appeared that mikrokline was always absent. The red colour of the 

 orthoclase is caused by a finely distributed reddish brown substance, 

 which disappears however as soon as the feldspar is altered into 

 kaoline. Biotite is indeed always present, but sometimes very scarcely 

 represented. It also occurs that by alteration it has been changed 

 into chlorite, and then, at the same time, rutile-needles appear. 

 Brown iron ore (limonite), in the shape of irregular flakes and accu - 



1) J. Ahlburg asserts (Versuch einer geologischen Darstellung Her Insel Celebes. 

 Geolog. und paleonlolog Abhandl. herausgeg. von J. F. Pompecki und F. von Huene. 

 N. F. 12. Jena 1913, page 110), that among others also Lias is found in Taliabu. Most 

 likely he mistakes — he is not so very particular — this island for Misol. Further, 

 he says, with regard to tlie demarcation strata of the Jurassic and the Cretaceous 

 system, that they "allerdings nach neueren Untersucliungen der Trias angebören". 

 There can neither be question of this, as is clearly proved by G. Boehm's essay 

 (Palaeontographica. Suppl. IV. 1904, pp. 1—40). Most likely Ahlburo has in this 

 respect mistaken Taliabu for Biu'u. (Vide: Ccnlralblatt f. Mineralogie 1909, 

 p. 561; 1910, p. 161). 



•) According to a communication of Mr. van Nochuvs the coral limestone reaches 

 only a height of + 10 m. 



3) Molukken- Verslag, p. 218. 



