Geology. -— "Geological data derived from the region of the 

 "Bird's head" of N ew-Guinea" . By Prof. L. Ruttkn. 



(Communicated at the meeting of March 24, 1923). 



Tlie great nortliwestern Peninsula of New-Guinea is one of the 

 least known parts of the Indian Arcliipeiago. In recent times some 

 data concerning it have been published by R. D. M. Vehbeek in 

 his "Molukken Verslag"'), and C. E. A. Wichmann, when journeying 

 from the east coast to Horna, discovered a folded coal-bearing for- 

 mation ') which proved to be of tertiary age '). 



In the last few years (between 1917 and 1921), however, explo- 

 rations were made on a large scale in Northern New-Guinea and 

 also in the "Birds head" for oil and coal, by the officers of the 

 Mining Department in the Dutch East Indies. The results of these 

 explorations have not been published as yet "), but some years ago 

 I received fi-om the Director of the Mining Department in the Dutch 

 East-Indies a rather large collection of limestones and marls for 

 examination. The study of this collection has been finished, but tiiere 

 would be little sense in expatiating on it here, a fortiori as a 

 description will probably be published elsewhere. II may be of 

 interest though, to summarize the obtained results. 



Although we are not quite sure that all the rocks we examined, 

 are of tertiary age, this may yet be assumed for the great majority. 

 Now, when observing on the subjoined sketch-map the localities 

 of "Bird's head" from which the examined rocks are derived, we 

 realize at once I hat tertiary deposits have a ivide distrbution in the 

 north-west part of Nein-Guinea. However, eocene rocks seem to he 

 scarce among the tertiary deposits, which is quite in keeping with 

 what we know about the other parts of New-Guinea. They were 

 found only in two regions: in the first place between the island 

 of Rumberpon and Horna, where, in two localities, Nummulites- 

 Alveolina limestone and Alveolina-Lacazina limestone have been 



') Jaarboek Mijnwezen Ned. Indie 1908. Wetensch. Gedeelte. 

 ») Nova Guinea. IV. 1917. 

 *) Nova Guinea. VI. 2. 1914. 



*) I. C. 0. -Commissie, The history and present state of scientific research in the 

 Dutch East Indies. Geology, p. 28. 1923. 



