(41J) 



volcanoes, besides the one just discussed and that in February/March 

 190J, is still to be slated: for J889 with re^ai-d to Roeang and 

 beginning- of Septemher for the submarine volcanic phenomena near 

 Mahengetan, perhaps 1893 for Lokon and 1898 and 1904 again for 

 Roeang; but quite as often even this vagne co-relalion cannot be 

 recognized ; so that in the end ojily so much can be admitted as 

 irrefutable for the Minahassa and neighbouring islands, that iji "eneral 

 an increase of the seismic agitation is accompanying the increased 

 volcanic activity of the last years. 



Before concluding these notes, I have to add some observations 

 about Mr. Ahlburg's statement, on the authority of native informers 

 that Sopoetan, at the last or perhaps at a former great eruption, 

 should have lost its summit and that then the great crater should 

 have been formed. (I.e. page 193). In the first place the cone as 

 seen from the north-side does not gi\e the impression of having 

 formerly been more pointed. With many of the so regular volcanic 

 mountains, with Sopoetan it is the case from the south-side, the 

 truncation of the crater-edge gives the impression as if the top of 

 the cone has been broken off by \'iolence. Indeed of most of these 

 mountains a story may be heai'd here or there, that such a cata- 

 strophe has really taken place, as with i,iJ^ so often a legend is to 

 explain why there is no pinnacle on a sti'ikingly obtuse tower. A 

 real st rato- volcano however begins its existence by the crater-orifice, 

 not by the cone, and this is certainly the case with Sopoetan with 

 its fine alternation of horizontally outcropping layers of coarser and 

 finer agglomerated material visible in the crater to great depth. If 

 in a strato-volcano the crater should ojily be chiselled out of an 

 existing cone by an eruption, then this implies a long previous 

 history, during which a former crater has entirely disappeared through 

 collapse and erosion. This how^ever will not make the mountain 

 more pointed but rather more obtuse and flat. Of course at every 

 great eruption a crater may be swept clean, and shaky pieces can 

 be blown off. In this sense some value might jierhaps be allowed 

 to the communicated story, which had remained unknown to me, if 

 it is really founded on tradition; though it is entirely excluded that 

 it can relate to an eruption that took place after Reinwardt's visit 

 to the volcano. The crater has certainly an unbroken appearance, 

 this needs however not plead a recent origin, but oidy proves that 

 the time (tf the last great eruption is not yet long ago. (I.e. p. i)6iy). 

 The structure of the crater and the great thickness over which the 

 shell-like superposed strata are visible therein, show on the conti'ary 

 that this volcano, as late as 19(Hó still the youngest of the system, 

 nevertheless may look back on a venerable duration of its activitv. 



28 

 Proceedings Royal Acad. Amsterdam. Vol. XIV. 



