Exploratory work in New Guinea is dangerous because of almost impenetrable forests, tropical diseases, unfavorable climatic conditions, hostility of uncivilized natives, and lack of interest by the Dutch in developing the area. The island of New Guinea is divided into three administrative parts, Dutch New Guinea, former German New Guinea, now under Australian mandate, and former British Papua, now under Australian mandate. The island is in one of the greatest zones of crustal weakness of the earth, which is described by a series of arcs extending from the Himalayas to New Zealand. Complex structural conditions are explained by great overthrusts. Tertiary sediments, intensely folded, mainly of shallow-water types, contain the evidences of petroleum, oil and gas seepages, brackish springs, and mud volcanoes. Beneath the Tertiary deposits the formations range from Mesozok: to Archaean.