In a passage, which is the continuation of that already cited, he writes: "(3) The microscopical structure and chemical composition of the beds of cannel coal and earthy bitumen, and of the more highly bituminous and carbonaceous shale, show them to have been of the nature of the fine vegetable mud which accumulates in the ponds and shallow lakes of modern swamps.

There is a fossile elastic bitumen found at Matlock in Derbyshire, which much resembles these substances in its elasticity and inflammability.

There is a fossile elastic bitumen found at Matlock in Derbyshire, which much resembles these substances in its elasticity and inflammability.