Listed as an artist in drawing and landscape in the 1851 Census for Cornwall, George P Marrack's address was given as either 1 Regent Square, Madron or 1 Morrab Place, Penzance.  At the date of the census he was 20 years old and unmarried, the Falmouth-born son of Mary Marrack, innkeeper. The Slater's Directory of Cornwall (1852/53) described him as a landscape architect. Later he became a victualler. 

A correspondent (2019) has been in touch with further information obtained while researching his ancestor George Marrack, who emigrated to Australia, and subsequently moved to the USA, settling in San Francisco.