XVII 



SYNOPSIS 



241 



First Order of the Olivine Basalts. 



Characters. — Olivine in abundance. Felspars of the groundmass 

 not in flow-arrangement. 



Formula. — Oliv., m.atr., cop., non-flu. 



Sub-order. 



Pyroxene 



of the 



groundmass. 



I. 



Granular 



(gran.) 



Prismatic 

 (prism. ) 



3-. 

 Ophitic 

 (ofik.) 



Section. 



Presence or 

 absence of plagio- 

 clase phenocrysts. 



Plagioclase 



phenocrysts 



(phen.) 



No plagioclase 

 phenocrysts 

 \. (non-phen. ) 



• 5. Phen. 



6. Non-phen. 



Genus. 



Character 



of the 



phenocrysts. 



Glassy plagioclase 



phenocrysts 



(vitr. ) 



Opaque plagioclase 



phenocrysts 



(opac.) 



Large phenocrysts 

 of olivine and 

 pyroxene, over 

 2 mm. (magn.) 



Small phenocrysts 



of olivine and 



pyroxene under 



2 mm. Pyroxene 



scanty and often 



absent (parv. ) 



5. Vitr. . 



6. Opac. . . 

 7 Magn. . . 



8. Parv. 



9. Vitr 



10. Opac 



11. Magn. . . 



12. Para. . . 



Species, 



}■ ■ 



Number of 

 specimens. 



Not repre- 

 sented. 



' Not repre- 

 sented. 



' Not repre- 

 sented. 



