Borings have been made only in the neighborhood of Azua. A pool known as "agua hedionda," "stinking water," had long suggested petroleum, and an American company known as the West Indies Petroleum Mining and Export Company undertook the development of the field. Oil was struck on November 14, 1904, the well spouting oil to a height of seventy feet and producing about 500 barrels per day. The grade of the oil was 22 Baume gravity with an asphaltum base. It was better than the average of Texas oil and was considered a good fuel and lubricating product. The main difficulty in this field was the presence of salt water above the oil (as is often the case in oil regions), which here came in rapidly at a depth of about 900 to 1000 feet. It was necessary to put a gate valve on the first well, keeping it enclosed for a period of six months, in order to prevent the damaging of the surrounding property from the flow of oil, as there were no storage tanks. During this time the continued agitation of the casing by the gas pressure and the looseness of the upper soils and shales let in the salt water and ruined the well, and, it is to be feared, to some extent affected the surrounding territory. The company sunk four wells more, all but one of which produced some oil, but as the salt water entered in such large quantities they were unable to penetrate below the 1200 feet level and were forced to abandon the wells at just about the depth where they expected to reach the real oil sand. The fifth well showed greater evidence of a genuine oil field than any drilled previously but for the same reason it could not be carried to the desired depth. At this point dissensions arose in the management of the company with regard to the method of drilling, the suggestion being made that a combination drilling machinery comprising what is known as the rotary process be adopted in combination with the old cable rig style. No agreement was reached, and operations were discontinued. Since the beginning of 1917 other interests have made investigations and it is rumored that development work will shortly begin. There are indications that if drilled with the proper appliances the field will yield excellent results. How far the Azua oil field extends is a matter of conjecture, but it has been estimated to cover an area of over 190 square miles.