23tt KEPORT— 1891. 



Lake Amadeus, and he has fixed the position of its western 

 margin, reducing the size of the lake to one-fourth of the area 

 assigned to it provisionally in the earlier maps. 



In New Guinea the energetic enterprise of Sir William 

 Macgregor is rapidly increasing our acquaintance with the 

 river-system and the highlands of the British territory, and with 

 the products of the various zones. His botanical collections, 

 as determined by Baron von Mueller since we last met, show 

 an extraordinary commingling of genera upon such portions 

 of the mountains as lie above the altitude of 11,000ft. In this 

 alpine region he has found representatives of Scandinavian, 

 Himalayan, Bornean, and Antarctic floras. The collocation 

 of these forms upon such isolated peaks, cut off as they now 

 are from their congeners by the tropical climate which invests 

 the bases of the mountains on which they live, adds to the 

 data already accumulated in support of the hypothesis of 

 climatic changes in past epochs. 



The torrential character of the rivers is indicated by the 

 fact that, whilst the sources of many of them are situated no 

 further from their mouths than seventy miles as the crow 

 flies, yet they have a fall which is often 13,00Qft. As the 

 last part of their courses is through flat swampy land, in parts 

 many miles across, the steepness of the grade is striking. The 

 erosive power of such streams is enormous, and it has fringed 

 the south-eastern end of the island with vast deltas hardly 

 rising above sea-level. These are built up of coarse conglo- 

 merates beneath and of fat alluvial soils above, through the 

 jungle-covered surface of which the streams wander to the 

 coast. 



The main ranges consist of schists and slates, traversed by 

 numerous quartz-veins, mostly barren of gold. The age of 

 these rocks is reported to be Silurian. The foothills are 

 largely composed of conglomerates, once continuous round the 

 ranges, but now broken up by erosion into isolated raised 

 patches. Volcanic rocks are distributed plentifully in the 

 river-beds, but the vents from which they have been derived 

 have not yet been discovered. 



The smaller and more distant islands which dot the Pacific 

 have not been neglected during the period under review, for 

 Mr. C. M. "Woodford has returned from his third visit to the 

 Solomon Islands, bringing with him the materials for a work 

 upon the physical features and the fauna and flora, which 

 should be a valuable supplement to Mr. Guppy's recent 

 volumes. Mr. Lindt has also spent some months on the New 

 Hebrides, and brings back with him a series of photographic 

 views of the people and their villages, together with others of 

 the volcanoes, the forest vegetation, the coral-girt shores, and 

 the fishing fleets, which have a considerable value. 



