George Main

I am looking at the Main Family Tree
I have these children so far in birth order

Hiram Main - BD July 31, 1832
Elizabeth Main - BD May 28,1836
George Main - BD December 17, 1836

There has to be an error here. Elizabeth and George are 7 months apart in
birth. Could the year be recorded wrong?

Can I find the birth records any where?

Thanks