Another Summers researcher recently discovered children we didn't know about belonging to William Summers and Mary Horn, namely David and Emby (and I'm so curious about the origins of the name Emby!). It appears they also migrated to Oakland County, Michigan, as did their mother Mary. Wow - great find!
This discovery lead me to review my family tree regarding the Summers relations who migrated to Michigan, and it's clear that in piecing together that puzzle, there was no shortage of confusion for me! But I think I have finally untangled it - or at least I'm closer. Here's the (current) low-down.
John Summers Sr., son of Georg and Barbara Sommer, married Anna Van Deren. They had 5 sons: George, David, John Jr., William, and Jacob. Of those, George, David, and William died before the 1830s when the migration to Michigan happened. The families of John Jr. and Jacob migrated to Sterling, Macomb, MI and later settled in Shelby. The descendants of David and William migrated to Oakland County - specifically they were found in Oakland and Avon townships. But what about the descendants of George who died in 1814? It appears that George might have had two wives: Sarah Hoagland with whom we think he had 4 children, and Clara Johnson with whom he had a daughter named Matilda. We still don't know anything about the children George had with Sarah, nor the mysterious Clara Johnson, the person listed on Matilda's death certificate as the mother. Research continues, but it appears that Matilda married Smith Scudder in New Jersey in 1831 and they traveled with Matilda's uncles to Macomb County, Michigan.
As for the question that originally made me realize that Summers had migrated to MI in the first place - that being the last will and testament of Ernest Mann (1773-1846) where he named his cousin Jacob Summers as executor and which at the time caused me to go HUH? - the answer is that Jacob Summers Sr. (1787-1863) was the son of Ernest Mann's mother's brother (Ernest's mother was Maria Magdalena Summers and her brother was John Summers Sr.), and thus first cousin of Ernest Mann. Aren't we glad that's all cleared up?
There's probably even more to the story of the Summers family and their migration from New Jersey to Michigan. But this seems like a pretty good snapshot!