GEOLOGY. 307 





facts which, I think, must be borne in mind not only in forming a 

 conclusion as to the origin of meteorites, but also in attempting to 

 explain volcanic action in general. 11 



ON TUE MOA, OR GIGANTIC BIRD OF NEW ZEALAND. 1 



At a recent meeting of the Linnean Society of London, Mr. T. 

 Allis exhibited some of the bones of the New Zealand Moa, in a most 

 perfect state of preservation, the same having been found under a 

 deposit of shifting sand. It had apparently been surprised whilst 

 sitting on its young ones, the bones of which were also found with 

 those of the parent. In the discussion which followed, Dr. Hooker 

 suggested that the perfect condition and high state of preservation 

 which the bones exhibited might possibly be the result of preservation 

 in ice, similar instances being on record, but the other speakers 

 took an entirely different view of the subject, and thought that the 

 bird to which these enormous bones belonged had probably been 

 living within ten years. If this conclusion be correct, it seems ex- 

 traordinary that no more precise information can be obtained from the 

 natives, a race remarkable for their intelligence; for, if so gigantic a 

 creature were living ten years ago, it seems impossible that no more 

 accurate information respecting it should exist than the vague and 

 most unsatisfactory reports which have been collected by English 

 emigrants. However, a very important point is settled in bringing 

 the history of the bird down to the time when New Zealand was 

 colonized by the British. It were indeed presumptuous to affirm that 

 a moa will still be found alive ; but the evidence now before us shows 

 that such an event is any thing but impossible. In considering this 

 subject, we must bear in mind that, being continually at war with the 

 natives, we are debarred from that free access to the interior, and from 

 that unrestrained exploration, which are absolutely necessary in such a 

 case as this. The wary character of the ostrich tribe is well known : 

 in the Great Sahara the ostrich himself is only to be discovered at an 

 immense distance, and yet there are no intervening objects behind 

 which he could shelter. It is very different in New Zealand : there 

 the moa, if possessed of half the subtlety of the ostrich, might escape 

 for years the notice of a few Europeans who have ventured to intrude 

 on his haunts. 



DISLOCATIONS OF THE EARTH'S CRUST. 



Dislocations of the earth's crust of various kinds, such as elevations 

 or depressions, arc accounted for by Dr. Bischof the eminent author 

 of the Elements of Chemical and Physical Geology in the following 

 manner. " Exhalations of carbonic acid are of universal occurrence, 

 and originate at great depths, for the deeper we penetrate the more 

 abundant they become. Hocks occurring at such great and inaccessible 

 depths are chiefly silicates, like the oldest of the known formations, 

 a fact which the volcanic eruptions of lava confirm. These silicates 

 are decomposed by carbonic acid ascending to the surface, the decom- 

 position being facilitated by the increase of temperature towards the 

 interior of the earth. The products are silicate of alumina and certain 

 carbonates, silica being displaced. When minerals or rocks combine 

 with other substances, not only an increase of matter, but also an 

 increase of volume takes place, provided that such combination does not 



