558 NOTICES OF NEW BOOKS. 



one or two others, the vast and almost innumerable multitude of 

 islands scattered throughout the Pacific, the Indian, and the At- 

 lantic Oceans are all composed either of volcanic or of modern 

 coral rocks (p. 125). This fact, singular as it is, is a manifest 

 extension of that law and the effect of the same causes, whether 

 chemical or mechanical, from which it results that a vast majority 

 of the volcanoes now in action either stand as islands in the sea or 

 are near its shores. 



" This fact of the Ocean islands being so generally volcanic is also intei'esting 

 in relation to the nature of the mountain chains on our continents, which are 

 compai-atively seldom volcanic, and yet we are led to suppose that where our 

 continents now stand, an ocean once extended. Do volcanic eruptions, we may 

 ask, reach the surface more readily through fissures formed during the first 

 stages of the conversion of the bed of the ocean into a tract of land?" (p. 126.) 



In the volcanic archipelagos the islands are generally arranged 

 either in single, double, or treble rows in lines which are fre- 

 quently curved in a slight degree. This arrangement in lines 

 seems to exist in a perfect series from a few volcanic islands 

 placed in a row, to a train of linear archipelagos following each 

 other in a straight line, and so on to a great wall, like the Cor- 

 dilleras of America. Along the shores of great continents also 

 there exist islands forming small volcanic groups, indicating, it 

 would seem, a relation, not only by proximity but in the direction 

 of the fissures of eruption, to the neighbouring continents, and in 

 some cases affected by the same volcanic disturbances. The lines 

 of intersection at the Galapagos, at the Cape de Verde archipelagos, 

 and the best marked line of the Canary Islands, are examples of 

 this relation, and in some of these cases eruptions have taken 

 place within the historical period on more than one of these 

 parallel lines of fissure. " Believing," says Mr. Darwin, " that a 

 mountain axis differs essentially from a volcano, only in plutonic 

 rocks having been injected instead of volcanic matter having been 

 ejected, this appears to me an interesting circumstance ; for we 

 may infer from it as probable, that in the elevation of a mountain 

 chain, two or more of the parallel lines forming it may be upraised 

 and injected within the same geological period." (p. 129.) 



D. T. A. 



II. Physical description of New South Wales and Van Diemen's 

 Land, accompanied by a Geological Map, Sections and Dia- 

 grams, and figures of the organic remains. By P. E. de 

 Strzelecki. 8vo. pp. 462. 



This work by the Count de Strzelecki is the result of five 

 years of continual labour occupied in travelling, on foot, for a 

 distance of as much as 7000 miles, through various parts of the 

 eastern shores of the vast island- continent of Australia and in 

 the island of Van Diemen's Land. The main object of the author's 

 visit to New South Wales, he states to have been to examine its 



