The incorporators were J.H. Jones, a local contractor; Ira Cadwallader, a local industrialist; Charles Ash, a local banker; and A.O. George, who talked them into it. During the summer of 1915 they got together as the Fostoria Light Car Company to produce four different models of a low-priced four-cylinder assembled car. "The Surprise Car of the Season," ads burbled. Although initially locating in the old Seneca Lamp plant, by December of 1915 they had bought out the Storm Buggy Company and were making plans to move there. A total of 293 Fostorias were built by September of 1916 when the company found itself in trouble. Reportedly, the problem was the engines Fostoria had bought from Sterling Motors in Milwaukee. They were lemons. A call was made to Le Roi. Believing that a change of image would help too, the Fostoria people reorganized in December as the Seneca Motor Car Company for the manufacture of a new car called the Seneca.

The Fostoria Seneca Motorcar company (organized in 1917) produced three to five automobiles per day and 80% of their production was exported to places such as Australia, Borneo and China. Seneca Motorcar prospered until Henry Ford developed the assembly line. Seneca couldn’t compete with mass production techniques and manufactured its last car in 1924.

The Seneca was the Fostoria renamed, because the latter had suffered a bad year. Ira Cadwallader, one of the original Fostoria stockholders, took over as president of the new Seneca Motor Car Company, and put his son, Lester in charge of managing the factory. The Seneca was a typical assembled car of the period and was a four for the whole of its life, LeRoi engines used through 1921 and Lycomings thereafter. Only open cars - tourers and roadsters - were built. Seneca enjoyed a modest success, with an annual output of several hundred cars, about half of them exported, the other half sold in the immediate area. Increasing competition in the industry ultimately saw the shutdown of the Seneca assembly line in 1924. There was no bankruptcy nor sale of assets. The Seneca company continued to make replacement parts for years afterwards.