8J1 



eruptions, however, is younger, according to a record of 'T Hoen, 

 who examined the coalfields of South Celebes. According to him, 

 probably a short time before the deposition of the tertiary limestones 

 had completely terminated, eruptions began all along the western 

 side of South Celebes, which gave rise to the high western moun- 

 tains; for the greater part they consist of tutfs, breccias and volcanic 

 conglomerates of andesites, basalts and also- of leucite-rocks. The 

 fragment of leiicitite, mentioned by von Steiger ^j, as originating 

 from a tutf between the coal-layers I and II of Bonto, appears on 

 closer examination to belong to a weathered eruptive rock, as estab- 

 lished by the engineer 'T Hoen. Considering that several weathered 

 intrusive rocks occur in the neighbourhood, it is rendered highly 

 plausible that the rock, from which the fragment of leucitite origi- 

 nates is also of an intrusive character; similarly the biotite leucite 

 basalt found by Bucking ") near Kantisang overlain by old-tertiary 

 limestone may also be an intrusive sheet. If so it would disprove 

 the hypothesis of an eocene age of leucite rocks in South-Celebes. 



Prof. Iddings, who travelled over this district in 1913, reports 

 that numerous intrusive rocks occur, as dykes, intrusive sheets and 

 perhaps as laccolites and as batholites, in the above-mentioned volcanic 

 series and also in the tertiary sandstones with coal-measures and 

 limestones. He mentions among others coarse grained shonkinites and 

 essexites. These, then, are still younger than the volcanic series, 

 which for the greater part is believed to be younger than the lime- 

 stones. As known, the limestones of this district are assigned partly 

 to the eocene and partly to the miocene period *). 



In addition we refer to Hotz *) who assumes tertiary (to miocene) 

 age for most of the basic eruptive rocks in the eastern peninsula of 

 Celebes. 



Available data, in some degree contradictory, seem to point out 

 that the violent eruptions in South-Central-Celebes may have begun 

 prior to the outbursts in South-Celebes; however, they may have 

 been contemporaneous for a consideral)le time, especially if the 

 volcanic formation in the former region goes back into the miocene, 

 as is deemed probable by Van Waterschoot van der Gracht. Anyhow 

 a considerable number of the tertiary igneous rocks in Celebes must 

 be of eocene age. 



1) H. VON Steiger. 1. c. p. 124. 



2) H. Bucking. 1. c. p. 000. 



3) R. D. M. Verbeek. Molukken Verslag 1 c. p. 55 seqq. 



1) W. Hotz. Vorlaufige Mitteilung iiber geologische Beobachtungen in Celebes. 

 Zeitschr. d. deutsch. geol. Ges. Monalsb. 1913 Bd. 65. p. 333. 



