THE PETROGRAPHY OF JAVA AND CELEBES 235 



partly separated from the matrix by small spaces or cracks, which 

 indicate that the magma was so stiff just before it solidified that 

 it pulled apart through stretching. In thin section there are small 

 phenocrysts of leucite, augite, magnetite, and reddish-brown 

 biotite, which has an outer zone with weaker absorption than the 

 central part, and in some instances has a margin filled with inclu- 

 sions. The groundmass consists of leucite, slender prisms of lime- 

 soda feldspar, minute prisms and anhedrons of augite, and 

 magnetite. The chemical analysis and norm show that the rock 

 is a little more femic than the variety first described, No. i, and 

 that it contains slightly less soda and normative albite. In place 

 of 39.5 per cent of normative orthoclase and 10.8 of normative 

 nephelite, there has crystallized abundant leucite and no nephelite. 

 The rock is leucite tephrite. 



The rock of analysis No. 3 is gray, dense, vitreous to sub- 

 vitreous, and aphanitic, and is from Kali Sekatak. It is mino- 

 physic and dopatic, with abundant small phenocrysts of augite. 

 In thin section the groundmass is seen to be holocrystalline and 

 to consist of lime-soda feldspar surrounded by alkalic feldspar, 

 besides anhedral crystals of alkalic feldspar and some leucite, 

 with minute crystals of augite and magnetite. The chemical 

 analysis and norm show this to be a still more femic variety with 

 less alkalies. No nephelite or olivine is recognizable in the rock, 

 and none was observed in Nos. i and 2. The rock may be classed 

 as a vicoite, or an orthoclase-bearing leucite tephrite. 



The rock of analysis No. 4 is light gray, and aphanitic, from 

 Kali Gillinan, It is dopatic, with small phenocrysts of augite, 

 but no megascopic crystals of leucite or feldspar. In thin section 

 it is seen to contain numerous small phenocrysts of augite, leucite, 

 and very small magnetites, ' in a holocrystalline matrix composed 

 of prismoid lime-soda feldspar, anhedral orthoclase, leucite, and 

 augite. The chemical analysis and norm are much like those of 

 No. 2, which, however, is characterized by large phenocrysts of 

 leucite. The rock is a variety of leucite tephrite with orthoclase, 

 related to vicoite. 



The rock of analysis No. 5 is medium gray, aphanitic, and very 

 porous, from Kali Sekatak, and has some large phenocrysts of 



