Geology. ''On the Miocene Fauna of the West- Progo Mountains in 

 Java'. By Prof. K. Martin. 



(Communicated in the meeting of June 30, 1917). 



Some years ago I made a few communications to this society on 

 the mountain range extending on the right bank of the Kali 

 Progo, west of Jogjakarta, and on the limestone found in 

 these "West-Progo Mountains"^). For the geographical and geological 

 details I refer to these provisional communications and to the more 

 elaborate description in my travelling journal, in which this limestone 

 is determined as lower Miocene, although the fauna found in it had 

 not been completely studied then '). All the material has now been 

 worked up, and in what follows I propose to give a short survey 

 óf the chief results of the examination of this fauna *). 



Two tinds of fossils are of special importance, the G o e- 

 n o e n g S p o 1 ó n g, near D j o e n g g r a n g a n, and the K e m- 

 bang Sokkóh, close to B o m a a s, of which the former yielded 

 69 different species and the latter 84, excepting corals and some 

 echinoidea, the investigation of which proved impossible on account 

 of the present circumstances *). 



The determined fossils are in the first place mollusca, especially 

 gastropoda, a few scaphopoda, some thirty lamellibranchiata and a 

 small number of foraminifera which have been examined by Dr. 



L. RUTTEN. 



The fossils of the G. S p o 1 ó n g have changed into a fine- 

 grained mass of clear transparent calcite, but nevertheless possess 

 only very little rigidity and easily disintegrate, when the marl filling 

 their cavities absorbs water. They are therefore difficult to prepare. 



1) "Enkele beschouwingen over de geologie van Java" (Verslag Mei 27, 1911) 

 and "Verdere beschouwingen over de geologie van Java" (Verslag Maart 30, 1912). 



2) Sammlungen des Geolog. Reichs-Museums in Leiden, Ser. I, Vol. 9, pp. 56— 

 76 and 108—111. 



3) The complete publication will appear in the organ of the Geological Minera- 

 logical Museum at Leiden, partly in order to retain the connection with other 

 related papers and partly on account of the circumstance that the special descrip- 

 tions are to be accompanied by a number of plates which could not very well be 

 incorporated in the Proceedings of the Academy. 



■*) The material necessary for comparison and the literature required were 

 inaccessible through the stagnation of international collaboration. 



