Lamar University paleontologist Jim Westgate believes the fossil discovered in the Ike-damaged town of Caplen is from a Columbian mammoth.
Westgate says the creature was common to North America until around 10,000 years ago.
Westgate had offered to accompany colleague Dorothy Sisk to her Bolivar Peninsula beachfront home after Ike hit. They found concrete and splintered pilings where her residence had been.
Then Westgate noticed something unusual mixed in with the shell debris in what had been Sisk's front yard.
Westgate recognized the fossil tooth, which looks like a series of boot soles or slices of bread wedged together.
The fossil, about the size of a football, is expected to be sent to the Texas Memorial Museum in Austin.