Five Shell Cans in a Row, 1920

The oil boom of the early 1920s, particularly at Shell's Signal Hill, California site, provided the company with an opportunity to penetrate the Los Angeles area with sales of Shell gasoline and petroleum products manufactured in its new refineries nearby. In 1922, Shell Company of California and Roxana Petroleum merged with Union Oil Company of Delaware to form a holding company called Shell Union Oil Corporation. Approximately 65 percent of the holding company's shares was held by Royal Dutch/Shell Group.