Fourth Order of the Olivine-Basalts.
Characters.—Olivine scanty. Felspar-lathes of the groundmass
in flow-arrangement.
Formula.—Oliv., matr., pauc., flu.
| Sub-order. | Section. | Genus. | Species. | Number of specimens. |
|---|
| Pyroxene of the groundmass. | Presence or absence of plagioclase phenocrysts. | Character of the phenocrysts. | Length of felspar lathes. |
|---|
| | | | | |
| 10. Granular (gran.) | | | 19. Plagioclase phenocrysts (phen.) | | | 37. Glassy plagioclase phenocrysts (vitr.) | | | ·02-·1 mm. | 2 |
| ·1-·2 " | 12 |
| ·2-·3 " | 6 |
| ·3-·5 " | |
| |
| 38. Opaque plagioclase phenocrysts (opac.) | | | ·02-·1 mm. |
| ·1-·2 " | 2 |
| ·2-·3 " | |
| ·3-·5 " |
| | |
| 20. No plagioclase phenocrysts (non-phen.) | | | 39. Large phenocrysts of olivine and pyroxene, over 2 mm. (magn.) | | | ·02-·1 mm. | | | Not represented. |
| ·1-·2 " |
| ·2-·3 " |
| ·3-·5 " |
| | |
| 40. Small phenocrysts of olivine and sometimes pyroxene, under 2 mm. (parv.) | | | ·02-·1 mm. |
| ·1-·2 " |
| ·2-·3 " | 2 |
| ·3-·5 " | 1 |
| | | | | |
| 11. Prismatic (prism.) | | | 21. Phen. | | | 41. Vitr. | | | | | | Not represented. |
| 42. Opac. |
| | | |
| 22. Non-phen. | | | 43. Magn. | | | | Not represented. |
| 44. Parv. | ·02-·1 mm. | 1 |
| | | | | |
| 12. Ophitic (oph.) | | | | | | Not represented. |
| | | | | |