VII. Kimeridge coal.
Of the bay where this coal is found, I have seen but the eastern part, about a mile to the east of Little Kimeridge, where the cliffs are cut down rather abruptly. These are composed of a slate-clay (Kirw.) of a greyish yellow colour, finely slaty, containing both animal and vegetable impressions. The leaves of which the rock is composed, become much more evident, after it has undergone some decay, or, when sound, after it has been exposed to the fire. It divides spontaneously into large tabular masses. The fracture of the rock is earthy, with many small specks and nodules of indurated clay. The outside of the rock is covered with a thin layer of calcareous spar. The specific gravity of the specimen I tried, was 2,052. The mass effervesces with acids, but the nodules of indurated clay do not.
This rock passes gradually to a bituminous shale. The first transition is to a slate-clay of a lighter or darker colour, the joints of which are covered with iron pyrites. It burns with a yellowish flame, giving out a sulphurous smell, and becomes afterwards of a light grey colour. The second transition is to a bituminous shale called Stony-coal, the spec. grav. of which is 1,319. Its colour is dark-brown without any lustre: it effervesces slightly with acids, contains no iron pyrites and burns readily with a yellowish rather smoky and heavy flame. The smell is bituminous but not sulphurous. The top and bottom of the Kimeridge coal consist of the slate-clay first described. At little Kimeridge on the shore, I saw several large blocks of a very hard, compact brown limestone, having a conchoidal fracture, and displaying a few specks of indurated clay: it had an external covering of a grey earthy colour, owing no doubt
