Hi Sheila! What state/county are we talking about? Each state has different probate statutes and different laws of descent and distribution (where stuff goes when there is no will).
Have you actually looked at the probate file? If there was an order to sell slaves, then there might be the sheriff's notification of an auction. If there were minor children, then a guardian/tutor (soe states called them that) would have been appointed.
Also might recommend looking at the land deeds from the decedents property and James's property (if I am following the family correctly). See where James got his property. And check the deed records anyway, as the administrator/estate would probably have deeded any land to the heirs.
I may respectfully disagree with Al, however. Modern usage is that an Administration is for intestate estates (no will), but I think they were less particular that far back. So I would definitely check to see if there was a will, just in case. But if there is not a will, I know of no state that would allow a nephew to inherit when there is living issue (children or grandchildren). But then, I certainly don't know everything! (Exceeption might be if she adopted a nephew).