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. | Section. | Genus. | Species. | Number of specimens. | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Pyroxene of the groundmass. | Presence or absence of plagioclase phenocrysts. | Character of the phenocrysts. | Length of felspar lathes and prisms. | |||||||||
| 7. Granular (gran.) | 13. Plagioclase phenocrysts (phen.) | 25. Glassy plagioclase phenocrysts (vitr.) | ·02-·1 mm. | 1 | ||||||||
| ·1-·2 " | 13 | |||||||||||
| ·2-·3 " | 5 | |||||||||||
| ·3-·5 " | ||||||||||||
| 26. Opaque plagioclase phenocrysts (opac.) | ·02-·1 mm. | |||||||||||
| ·1-·2 " | 4 | |||||||||||
| ·2-·3 " | ||||||||||||
| ·3-·5 " | ||||||||||||
| 14. No plagioclase phenocrysts (non-phen.) | 27. Large phenocrysts of olivine and pyroxene, over 2 mm. (magn.) | ·02-·1 mm. | Not represented. | |||||||||
| ·1-·2 " | ||||||||||||
| ·2-·3 " | ||||||||||||
| ·3-·5 " | ||||||||||||
| 28. Small phenocrysts of olivine and sometimes pyroxene, under 2 mm. (parv.) | ·02-·1 mm. | Not represented. | ||||||||||
| ·1-·2 " | ||||||||||||
| ·2-·3 " | ||||||||||||
| ·3-·5 " | ||||||||||||
| 8. Prismatic (prism.) | 15. Phen. | 29. Vitr. | ||||||||||
| 30. Opac. | ||||||||||||
| Not represented. | ||||||||||||
| 16. Non-phen. | 31. Magn. | |||||||||||
| 32. Parv. | ||||||||||||
| 9. Ophitic (oph.) | 17. Phen. | 33. Vitr. | ·02-·1 mm. | |||||||||
| ·1-·2 " | 3 | |||||||||||
| ·2-·3 " | 1 | |||||||||||
| ·3-·5 " | 2 | |||||||||||
| 34. Opac. | Not represented. | |||||||||||
| 18. Non-phen. | 35. Magn. | Not represented. | ||||||||||
| 36. Parv. | ||||||||||||
Fourth Order of the Olivine-Basalts.
Characters.—Olivine scanty. Felspar-lathes of the groundmass
in flow-arrangement.
Formula.—Oliv., matr., pauc., flu.