Trying to find that out - I have a feeling it was anywhere on the field for a time but that he was the only player who could do this. The first goals appear not to have had crossbars either.
Anyway, I now have dates for a couple of other things soccer-wise: offside in its modern form came into being but with three players not two in 1866 before being revised down to two in 1925; penalty kicks were introduced in 1891. The only change to the rules since 1925 has been the introduction of substitutes and outlawing a deliberate backpass to the goalkeeper.