XVII 



SYNOPSIS 



243 



Third Order of the Olivine-Basalts. 



Characters. — Olivine scanty. Felspars of the groundmass not 

 in flow-arrangement. 



Formula. — Oliv., matr., pauc, non-flu. 



Sub-order. 



Pyroxene 



of the 



groundmass. 



7- 

 Granular 

 {gran.) 



Prismatic 

 {prism.) 



9-. . 

 Ophitic 



{opk.) 



Section. 



Presence or 

 absence of plagio- 

 clase phenocrysts. 



?3- 



Plagioclase 



phenocrysts 



{phen.) 



14. 



No plagioclase 



phenocrysts 



{non-phen.) 



' 15. Phen. . 



16. Nonphen. 



17. Phen. 



^ 18. Nonphen. 



Genus. 



Character 



of the 



phenocrysts. 



c 25. 



Glassy plagioclase 



phenocrysts 



{vitr. ) 



26. 



Opaque plagioclase 



phenocrysts 



{opac. ) 



27. 



Large phenocrysts 



of olivine and 



pyroxene, over 



2 mm. {magn.) 



Species. 



Length of 

 felspar lathes 

 and prisms. 



28. 



Small phenocrysts 

 of olivine and some- 

 times pyroxene, 

 \. under 2 mm. {parv. ) 



29. Vitr. . 



30. Opac. 



31. Magn. 



32. Parv. 



33. Vitr. 



34. Opac. . 



35. Magn. 



36. Parv. 



Number of 

 specimens. 



I 



5 



Not repre- 

 sented. 



Not repre- 

 sented. 



Not repre- 

 sented. 



3 

 I 

 2 



Not repre- 

 sented. 



Not repre- 

 sented. 



R 2 



