XXIV PALAGONITE 



339 



situ," the spaces between the fragments being filled with pala- 

 gonite. It would seem from the peculiar erosion of the glass 

 fragments that after the crushing a liquid magma occupied the 

 nterspaces, and afterwards solidified and underwent the pal agon itic 

 :hange. 



In this connection it is noteworthy that in the sections of the 

 ,ower hemicrystalline portion of the flow there are shown in the 



J [agma-lakelet, '25 mm, in size, magnified 290 diameters, from a basalt at Navingiri. 

 The groundmass, which is a smoky devitrified glass containing abundant felspar- 

 lathes, is coloured black. The magma-lakelet is pale yellow in the slide and 

 displays concentric lines of congelation. It behaves like palagonite. 



groundmass collections of a palagonitic material forming, as I 

 l ave termed them, " magma lakelets " of microscopic dimensions 

 ( 25 mm. in average size). These " lakelets " are irregular in form, 

 a id are not uncommon amongst a certain type of basaltic rocks. 

 ( ine of them is figured above ; and it may be added that they are 

 h 2st examined when displayed in a groundmass containing much 



z 2 



