GeologicaIly, 1ndonesia is complex. 1st consists of groups of large and small islands, situated between the Asiatic and the Australian Continents, and extends from 60 N. lat. to 110 S. lat. and 950 to 1400 E. long. The Archipelago is a heterogeneous geosyncIinal area divided into two dissimilar regions. One, the northwestern region, has been stabIe sin ce Pleistocene times; it has a quiet, reg…