Sorry, just re-read your message. I see now why I couldn't find George in 1891! And you mention another child of James & Catherine.

Do you know what happened to Margaret Quayle? Could it be that James & Catherine took George with them to America to help out the unmarried Margaret, especially if they had no child of their own at that point? If I let my imagination run away with me, perhaps the father encouraged or assisted with the arrangement and emigration to remove the evidence of 'indiscretion' and avoid scandal, especially if he was a wealthy property owner. Perhaps he feared the child might make financial demands later on.

Sorry again for so much speculation/fiction. Perhaps I should write a nove!