In 1899, Lucas visited the Sour Spring Mound south of Beaumont, Texas, with Pattillo Higgins. This was the future site of Spindletop. Lucas noted, "This mound attracted my attention on account of the contour, which indicated possibilities for an incipient dome below, and because at the apex of it there were exudations of sulphuretted hydrogen gas. This has suggested to me, in the light of my experience at Belle Isle, that it might prove a source of either sulphur or oil, or both." Lucas then signed a lease agreement with the Gladys City Oil, Gas, and Manufacturing Company, and a separate agreement with Higgins.