Pen and ink, watercolour and carriage oils on board

Pen and ink, watercolour and carriage oils on board (brown, black, blue, pink) [design for a] Single Brougham carriage (with flaps revealing a design with large or small front box, with or without rumble seat and/or top box) / J Gilroy, [Barker & Co., London], [ca1850] scale 1/2": 1' (1:24), 15.2 x 25.4 cm.