From the globe book:
**ARRO OIL CO. - LEWISTON, MT:
Founded in July 1921. In July 1925 they absorbed Montana properties of Pure Oil of South Dakota. Arro, in turn, sold off their marketing to Midwest in 1929, continuing in refining through 1941, with wholesale marketing only.
**MIDWEST REFINING CO. - CHEYENNE, WY:
Midwest was a Rocky Mountain producer/refiner when Standard of Indiana purchased controlling interest in the company in 1917. In 1928, Midwest entered the gasoline market, purchasing Arro Oil and Refining of Lewiston, Montana, Aero Oil Co. of Cheyenne, Wyoming and 75 gas stations in Colorado and New Mexico from A.A.Vickers. The Midwest brand name replaced the individual brands. In April 1930, Standard of Indiana purchased the entire Midwest marketing and rebranded the stations Standard in late 1931. The Midwest subsidiary, Utah Oil Refining Co., having ventured into gasoline marketing, continued to market under the Utah Oil brands.