Mountaineer was a motorcycle produced between 1902 and 1903, by International Motor Car Co., Ltd., of 76, High Street, Baker Street, London, which claimed to have works in Coventry.
The company offered a machine that was typically primitive. A heavy-duty bicycle had an engine clamped within the main frame and belt drive to the rear wheel.
In reality, the motorcycles were made by Rex, but when Rex moved on to a new design, the Mountaineer faded from sight.
Sources: Graces Guide, et al.