::The solid, essentially infusible form of petroleum is called pyrobitumen. It occurs in veins [[length::1 mm]] to [[length::8 m]] across and appears to have been injected or is a dead seepage. | ::The solid, essentially infusible form of petroleum is called pyrobitumen. It occurs in veins [[length::1 mm]] to [[length::8 m]] across and appears to have been injected or is a dead seepage. |