32. Basalt, like that below it.
31. Basalt, firm, compact, black rock, with a rough, green earthy band, from 6 inches to a foot, at the bottom, and becoming again very slaggy at the top.
30. Green shale like that below the underlying limestone, a few inches in thickness.
29. Coarse, green, sandy tufaceous limestone, averaging 1 foot in thickness.
28. Black shale with plants, 12 or 14 feet, becoming green and tufaceous at the top.
27. Basalt—the most striking of the whole section—a fine compact black olivine-bearing rock, beautifully columnar, 30 feet. The columns reach to within a foot of the bottom of the bed and cease about 10 feet from the top, the upper portion of the bed being massive, with vesicles which are drawn out parallel to the bedding of the series. The lowest part of the bed is a broken brecciated band, 3 or 4 inches thick. (See [Fig. 171].)
26. Black shale with fragmentary plants, 3 feet.
25. Basalt, with plentiful olivine, 12 to 16 feet. The base is not highly scoriaceous, but finely vesicular. Towards the top it becomes green, earthy and roughly brecciated. It partly cuts out the tuff underneath.
24. Tuff, green, fine-grained and well-stratified, consisting chiefly of fine volcanic dust, but becoming coarser towards the top, where it contains lapilli and occasional bombs of highly vesicular lavas.
23. Black carbonaceous shale, 3 feet; approaching to the character of an impure coal in the lower part, and becoming more argillaceous above with some thin nodular calcareous bands.