PRE- TERRES TRIA L HIS TORY OF ME TEO RITES 627 



result of strains of various kinds, record of which is to be 

 found in the structure of meteorites. Fissures will be formed, 

 into some of which pasty metallic matter will be forced from 

 below, and which will, in its passage upward, enclose angular 

 fragments of the siliceous crust. Other fissures occurring only in 

 the siliceous portion of the globe will give rise to the formation of 

 quantities of angular fragments, which will be cemented together 

 again by pressure to form breccias. Such fissures would be com- 

 paratively large, and affect a considerable area of the globe. 

 Other minor fissures would form in ramifying networks, which 

 would be filled by adjacent substance penetrating in a more or 

 less liquid form. Differential movements of solid portions, 

 without the existence of fissures, would produce slickensided 

 surfaces. Finally, the progressive disruption of the body occurs. 

 To produce this, two or three forces may be appealed to. In the 

 first place, there is the familiar fissuring from shrinking and 

 contraction as the body passes from the liquid to the solid 

 state. It is perfectly evident that a certain amount of this is 

 taking place upon the earth. ^ Meunier suggests further, that 

 in the moon we can see this process extended as much farther 

 as the moon is more fully cooled than the earth, and he regards 

 the well-known bright streaks of the moon as enormous fissures 

 {rahiures^ showing a progressive disruption of its mass.^ While 

 few probably at the present day would accept this interpretation 

 of the brio^ht streaks of the moon, there are numerous other 

 indications that the moon is considerably fissured. Meunier 

 also points to the asteroids as an illustration of a dismembered 

 heavenly body. 



In the second place, strains corresponding to the tidal strains 

 of the earth would produce a constant disruptive effect ; and, in 

 the third place, the recent investigation of Professor Chamberlin,3 

 has shown how the fragmentation of a small body may take 

 place by near approach to a large one. 



Once the body is broken up, its fragments may be drawn out 



' See Chamberlin, " On a Possible Function," etc., Jour. Geol., Vol. IX, No. 5. 

 ^ Cours de Geologic Comparee, pp. 258 et seq. 3 Op. cit. 



