Warren:

I have not found a "Medcalfe" as a surveyor, but did find a Simon Metcalfe, who is listed on a few maps as the Deputy Surveyor General of New York in the late 1760s and early 1770s. 

The work, Maps and Plans in the Public Record Office, vol. 2, America and West Indies, London, 1974 lists maps of Lake Champlain, 1763 and 1767, the Province of New York, 1768, Hardenbergh Patent, 1771 and another of parts of the land between the Hudson and Connecticut rivers 1771. 

I don't know if this is your man, but it might be; if you come by the library, I'll show you the references.

Jim