George R Lassiter (aft1816-1859)

Lassiter
Just checking some dates in our ancestor book, and realized my 4th greatgrandmother, (Alley Lassiter) and her son, (George R Lassiter) died on the same day! October 1 1859.
 * Alley Unknown (1802-1859), born in Georgia (U.S. state).
 * George R Lassiter (aft1816-1859)

How do I find the cause of their deaths?

Also no one knows her maiden name. Just recorded as Alley, born 1802, in Georgia, USA.

Help if you can, Michelle mikeshell863@yahoo.com