During geological ages different parts of the earth’s surface have alternately been raised and submerged. When above sea level they have been at times subjected to disintegration and removed by such agencies as water, wind, and glaciers, and when submerged the same localities have received deposits, as we now see being made under the ocean and at the mouths of rivers. As all the geological formations which are stratified have been deposited in their respective localities while that part of the earth’s surface was under water, and as oil is, almost without exception, found in these formations, we are able to account for the fact that petroleum is frequently discovered in localities which are now at a great distance from the sea. It would also explain why oil is frequently found in association with salt--a circumstance which had its accidental bearing on the earlier development of the petroleum industry in the United States. Many other arguments have been adduced supporting a belief in the vegetable origin of petroleum that would be worth discussing at length, were this a scientific treatise. Much controversy still prevails. The holders of the inorganic theory who assume that petroleum could be formed by chemical reactions from minerals are for the most part chemists who base their conclusions on laboratory experiments; whereas the scientists who hold by the organic theory are geologists, who base their contentions on actual investigations of the earth’s crust and the records of its changes as written in the rocks. The assumption is that the organic matter, after being imprisoned in the sedimentary rock by the processes indicated, under the influence of heat and pressure in some cases assumed the form of coal; in other instances succumbed to decay; while in other cases it formed crude petroleum and gas. It is assumed that a mere fraction of the organic matter which was gradually imprisoned in the formation of sedimentary rock would have been sufficient to create incalculable stores of oil and gas. The mode of decomposition by which these elements were generated is one of Nature’s secrets; and the stage in the history of oil-bearing rock in which the necessary chemical transformation took place is equally a matter of conjecture. As has been said, the presence of salt is a prevalent phenomenon in connection with oil deposits the world over. Not only is a strongly saline water commonly present in the vicinity of petroliferous rock, but in a number of fields oil is closely connected with large masses of rock-salt, gypsum and dolomite. An important fact which makes definite conclusions difficult is that in its world-wide distribution petroleum is to be found in almost the whole range of strata which forms the earth’s crust; from the earliest or Laurentian rocks to the most recent formations of what is known in geology as the Quarternary period.