28 



GEOLOGY. 



but the presence of such scattered lumps of iron in the basalts of Green- 

 land l at least limits the force of the inference. It suggests that either 

 the mass was very viscous, or that the metallic material was very inti- 

 mately diffused through the rock-substance previous to the beginning 







mt : -^' M^^^^^P^ 



^I^Ks^^j 







P^"* ' ' ' Jfe- V ^Ififflflr 



^5 *"• Mr 



»-■ «*** 



Fig. 6. — Section of the Dhurmsala meteorite, showing a large, somewhat porphyritic 

 chondrus inclosing a smaller monosomatic one. Both are composed of chryso- 

 lite. X8. (After Tschermak.) 



of crystallization, or that the motion of the molten mass was too great 

 to permit gravitative segregation, or that these influences combined 

 their effects. In addition, it is to be noted that a prolonged high 

 temperature, acting on a mixed mass of material, may furnish condi- 

 tions suitable for slow aggregation and crystalline rearrangement 

 without the melting-point being reached, and that this also may be 

 one of the agencies by which these singular combinations are produced. 

 It is hard to believe that these coarse crystallizations could have 



1 For a careful description and figures, see The Rocks of the Nugsuaks Peninsula, by 

 W. C. Phalen, Smithsonian Misc. Coll., Vol. I, Pts. 1 and 2, p. 198, 1904. 



