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THE POPULAR SCIENCE MONTHLY. 



ultimately become known. The island has 

 furnished such an abundance of important 

 and prominent new types, that, as respects 

 plant life, it may be regarded as one of the 

 most interesting and beautiful parts of the 

 earth. The close relationship often sup- 

 posed to exist between the north Australian 

 flora and that of New Guinea has not been 

 confirmed. It is true that the savannas of 

 the Fly River, covered with eucalyptuses, 

 myrtacea?, and proteaceae, correspond not 

 only in their outward habitus, but also in 

 composition, with the formation of York 

 Peninsula; but the typical Australian flora 

 is quite foreign to New Guinea, and there is 

 no ground for the supposition that the isl- 

 and was at one time inhabited by Australian 

 species. The palm flora of the island is one 

 of the richest in the world ; almost every 

 district is distinguished by endemic species. 

 The age of the island must be very great ; 

 the large number of indigenous genera and 

 species testify to this ; of the former, at least 

 fifty are already known. 



Geographical Development of Coast- 

 lines. — Summing up the points of his paper 

 in the British Association on the Geographi- 

 cal Development of Coast-lines, Prof. James 

 Geikie arrives at the general conclusion that 

 the coast-lines of the globe are of very unequal 

 age. Those of the Atlantic were determined 

 as far back as Paheozoic times by great 

 mountain uplifts along the margin of the 

 continental plateau. Since the close of that 

 period many crustal oscillations have taken 

 place, but no grand mountain ranges have 

 again been ridged up on the Atlantic sea- 

 board. Meanwhile the Palaeozoic mountain- 

 chains, as was shown, have suffered ex- 

 tensive denudation, have been planed down 

 to the sea-level, and even submerged. Sub- 

 sequently converted into land, wholly or par- 

 tially as the case may have been, they now 

 present the appearance of plains and plateaus 

 of erosion, often deeply indented by the sea. 

 No true mountains of elevation are met with 

 anywhere in the coast-lands of the Atlantic, 

 while volcanic action has well-nigh ceased. 

 In short, the Atlantic margins have reached 

 a stage of comparative stability. The trough 

 itself, however, is traversed by at least two 

 well-marked banks of upheaval — the great 

 meridional Dolphin Ridge, and the approxi- 



mately transmeridional Faroe-Icelandic belt 

 — both of them bearing volcanic islands. 

 But while the coast-lands of the Atlantic 

 proper attained relative stability at an early 

 period, those of the Mediterranean and Carib- 

 bean depressions have up to recent times been 

 the scenes of great crustal disturbance. Gi- 

 gantic mountain-chains were uplifted along 

 their margins at so late a period as the Ter- 

 tiary, and their shores still witness volcanic 

 activity. It is upon the margins and within 

 the troughs of the Pacific Ocean, however, 

 that subterranean action is now most remark- 

 ably developed. The coast-lines of that great 

 basin are everywhere formed of grand uplifts 

 and volcanic ranges, which, broadly speak- 

 ing, are comparable in age to those of the 

 Mediterranean and Caribbean depressions. 

 Along the northeast margin of the Indian 

 Ocean the coast-lines resemble those of the 

 Pacific, being of like recent age, and simi- 

 larly marked by the presence of numerous 

 volcanoes. The northern and western shores, 

 however (as in Hindostan, Arabia, and East 

 Africa), have been determined rather by re- 

 gional elevation or by subsidence of the ocean 

 floor than by axial uplifts — the chief crustal 

 disturbances dating back to an earlier period 

 than those of the East Indian Archipelago. 

 It is in keeping with this greater age of the 

 western and northern coast-lands of the In- 

 dian Ocean that volcanic action is now less 

 strongly manifested in their vicinity. 



The Story which Scenery tells. — "The 

 law of evolution," said Prof. Archibald Geikie 

 at the British Association, "is written as 

 legibly on the landscapes of the earth as on 

 any other page of the book of Nature. Not 

 only do we recognize that the existing to- 

 pography of the continents, instead of being 

 primeval in origin, has gradually been devel- 

 oped after many precedent mutations, but we 

 are enabled to trace these earlier revolutions 

 in the structure of every hill and glen. Each 

 mountain-chain is thus found to be a memo- 

 rial of many successive stages in geograph- 

 ical evolution. Within certain limits, land 

 and sea have changed places again and again. 

 Volcanoes have broken out and have become 

 extinct in many countries long before the 

 advent of man. Whole tribes of plants 

 and animals have meanwhile come and gone, 

 and in leaving their remains behind them as 



