I was looking around after reading about the extinct volcano under Jackson, MS, and stumbled across this info. I thought it was interesting, and it made me realize there are several extinct volcanos in the area. After staying up all night June 2011 watching the extinct Nabro volcano erupting in Africa, well, makes you wonder.

[link to www.newsouthernview.com]

“And even though it’s buried about half a mile deep below Jackson, we feel the affects of it today: hot water in excess of 100°F, carbon-dioxide gas, hydrogen sulfide gas from an 18,000 foot deep well near Piney Woods measuring 320°F [at the bottom of the well], and the natural gas in the gas rock. But also, apparently—the volcano is still pushing up a little bit.”

And

"The Jackson Volcano is on the east side of this syncline and the Monroe Uplift, another Cretaceous volcano, is on the west side. They’re kind of symmetrical. Further north is the Murfreesboro, Arkansas Volcano. And then, there’s a buried volcano at the mouth of the Mississippi River called the Door Point Volcano."