6. Form of basaltic dykes at Gregory's Valley, St. Helena.
So that one had been forced from its position by another long subsequently to its formation.
The general form of Gregory's Valley is a large basin bounded by a lofty precipitous mountain on one side called The Barn, and having a very narrow opening seaward, through which a small stream has cut its way. A remarkable circumstance connected with the basaltic dykes is that they are composed of a more compact basaltic rock than the basalt which they penetrate, so that whilst the rock has mouldered away these basaltic dykes have remained standing; and, as in the progress of their decay they split up, they present the appearances of walls built by human hands, with regular layers of stones, and which traverse the ravines of the island in all directions.
As might be expected, I found regular basaltic crystals in this valley, and also a variety of quartz ore, and other crystals, in the veins traversing the basalt. I also found the following remarkable section:
7. Geological Section from Gregory's Valley, St. Helena.
This was in a side valley or ravine leading from Gregory's Valley in a southerly direction.
On going down to the sea I found many species of starfish. I brought away three species of these with me. Two Species Pentagonal; one species Quadrilateral.
First species Pentagonal length of side 0.55 inch.
Second species Pentagonal length of side 0.50 inch.
Quadrilateral length of side 0.55 inch.