The debris forming the rocky strata may have been partially derived from the vol canic dikes piercing the field, but in all probability the sedimentary matter was derived from more distant sources. It is not essential, however, to the correctness of the theory given that the hydro-carbons should be derived in part or in whole from the heat of local volcanic action, nor do we feel at all confident that such was the case. It is equally or perhaps more probable that both the regions of heat and the sources of the rocky material were remote from the English fields of bituminous coal. We find our Western coal-fields and the accompanying strata over a thousand miles from their sources of pro duction.
Petroleum has been produced and utilized for centuries in Burmah, and it is reported the production has amounted to over half a million barrels annually. The wells do not appear to be deep, but are generally large excavations, into which the oil rises con tinually, giving off its more volatile parts and remaining as a heavy oil. Nothing posi tive has come beneath our notice in regard to the geology of this district, though it has been said that small seams of impure coal or bitumen exist below the oil-wells. Our impression is that it must be a volcanic region, and that the oil is constantly produced as it is produced in Cuba and Trinidad, rising from the volcanic sources of heat through the strata to the surface.
The naphtha of Persia has been celebrated for a long period, and has been used for sacred oblations and light in the pagan temples for ages. It is lighter than the Penn sylvania petroleum generally, but about the consistency of the oils produced from our deep wells. In regard to the formation and geological character of the Persian naphtha we can say nothing.
In China petroleum has been It is found in several localities; but we have only one to note, in which it exists in much the same geological condition and position as it is found on the Great Kanawha in connection with coal and salt. The oil is very light when first exposed, or when found at a great depth from the surface, but becomes thick on exposure. Gas is frequently struck in the salt-wells, which are often over 1500 feet deep; and sometimes its discharges are so violent and terrific as to suspend all operations in the vicinity.
When the gas thus emitted becomes ignited, the effects are tremendous and fearful, as shown by late experience in Northwestern Pennsylvania, and by former accidents on the Great Kanawha.