Clark Saunders is not sure that this Christian is the daughter of George. She married William Langlands, with whom his nephew, George Clark would later work. Their son was William Langlands Jr (1818-1889) who emigrated to NZ and became very well known there as a JP and a politician.

From Clark Saunders:
“According to "The Cyclopedia of New Zealand", a William Langlands (1817-1883) was born near Edinburgh and emigrated to Dunedin where he became a JP and politician; he arrived at Port Chalmers on the "Eden" in 1850, entered service of the Provincial Government as a draughtsman and later became Provincial Engineer for Otago.  He bought a considerable block of land in Dec Street, Invercargill, and built substantial buildings on the property -- known as the Langlands block.  He married a Miss Leggie in 1835.  The dates given by this source don't quite match the ones I have for our relative, but it would be hard to imagine they are 2 different men.  Assuming, they were one and the same, I wonder whether the decision of Adam Sprott Clark to emigrate in 1857 may have been influenced by his having a cousin already there.”