Richardus de Merston son of Nigel fitz Erfast, tenant of Marston in the Bedfordshire honour of Cainhoe. Occurs in the 1140s. Nigel de Merston, presumably his son, held three fees of the honour in 1166. [Domesday Descendants p582]
Sources:
1. Title: Domesday Descendants, A Prosopography of People Occuring in English Documents 1066-1166; K B S Keats-Rohan {2002} Page: 582