Marrs McLean, oilman, son of Edward Curd and Zerena (Marrs) McLean, was born in Sherman, Texas, on June 20, 1883. His father was a lawyer. McLean was known as the "second prophet of Spindletop" because he found oil on the flanks of the old Spindletop salt dome in Beaumont. The family moved to Beaumont in 1901 so the elder McLean could assist his son-in-law, also an attorney, with litigation resulting from the discovery of the first Spindletop oilfield. McLean attended Austin College and the University of Texas law school but left before he completed a law degree. He worked in Louisiana as a section hand and then returned to Beaumont, where, after a brief truck-farming venture, he bought a small interest in several wells being drilled on the flats near Spindletop Hill. In 1910 he and L. F. Benckenstein brought in a small well near Vinton, Louisiana, marking the first time that oil was produced on the flank of a salt dome.
In 1914 McLean fully evolved his flank-drilling theory, contending that the salt plug, as it thrust upward to form the dome, tilted the various strata to form traps that collected oil on the sides of the dome. Two years later he drilled on the flanks of the High Island dome, but without success. Undiscouraged, McLean began leasing every available acre on the flanks of the old Spindletop Hill. Unable to convince the major oil companies to drill on his leases, he approached a neighbor, Beaumont oilman M. Frank Yount, who accepted. On November 13, 1925, Yount brought in a well on one of McLean's leases on the south flank of the hill. The well produced 5,000 barrels of oil a day and launched a new Spindletop oil boom in Beaumont. In 1927 alone the field produced 21,000,000 barrels of oil. That year McLean brought in Cade No. 11, the well that made High Island an important flank field.
In the early 1930s McLean sold out of the drilling and producing business, and in 1937 he moved to San Antonio and turned his attention to politics. He was appointed finance chairman of the Republican party of Texas in 1938 and held the position until 1952. In 1946 he served as a member of the Republican National Finance Committee. As a key figure in Robert A. Taft's Texas organization, he worked to secure the presidential nomination for the Ohio senator in 1952. McLean married Verna Hooks in 1918, and they had one daughter. Together the McLeans donated funds to Baylor University to finance the construction of a physical-education building in 1938 and the Armstrong Browning Library in 1951. Baylor awarded McLean an honorary degree in 1951. He died in San Antonio on May 18, 1953, and was buried in Magnolia Cemetery, Beaumont. The Marrs McLean Science Building at Baylor University was built with funds donated by his widow.