The work was then carried on by Portlock as the geological branch of the Ordnance Survey, and the chief results were embodied in his Report on the Geology of the County of Londonderry and of parts of Tyrone and Fermanagh (1843), an elaborate and well-illustrated volume in which he was assisted by Thomas Oldham.

For a short time, commanding officer at Dover, when the Council of Military Education was formed in 1857, he was selected as a member.

[1] During these years of active service, he contributed numerous geological papers to the scientific societies of Dublin and to the British Association.

He wrote a Memoir of the late Major-General Colby, with a Sketch of the Origin and Progress of the Trigonometrical Survey (reprinted in 1869 from Papers on Subjects connected with the Royal Engineers, vols.

Fanny was the 4th daughter of Major General Charles Turner, KH commander of the Cork District.