Most fuel companies in the pre WW2 era sold a sub-regular grade of gasoline that didn't contain lead and sold at a discount -- Texaco stations featured "Indian Gas," Shell sold "Silver Shell" or "Green Streak," and so forth. Consumers Union Reports crusaded against the use of lead in fuel in the late 1930s, and found that these sub-regular grades performed fine in most cars of the period. Amoco even stressed its lack of lead as a benefit in its advertising, not mentioning that they used benzine instead.
"Indian", "Fire Chief", and "Sky Chief" are or were registered trademarks of Texaco Inc
14 January 1931 - 15 March 1943 Indian Refining Company continues in operation as an "affiliate" of The Texas Corporation, although all sales outlets and company facilities and equipment are re-badged as "Texaco".
"Indian" gasoline becomes a "sub- regular" (priced below "Texaco" gasolines) and is added to the product line at most outlets, nation-wide.
(thanks Bruce!) It is during this period that "Indian" pumps bear this distinctive plate - either round or rectangular - featuring an art deco Indian beadwork design.
October 1938 "Texaco Sky Chief Gasoline" is introduced (replacing "Fire Chief Ethyl").