Digging a hole to China

Thoreau used this phrase in the 1850s about a hole his neighbors were digging. What is the origin of this expression? Does anyone know of an earlier usage than Thoreau's?

In the UK the expression is 'to Australia' (for fairly obvious reasons it is different from the US). It is used when a hole is so deep that it is (humorously) supposed to be going to go right through the earth and come out the other side.