It seems that roughly 35 million years ago, we had a barrage of asteroids.

One crater is in Chesapeake Bay off the Maryland coast. The other, called the Popigai crater, is in north-central Siberia. Estimates of their age suggest they were created a mere 10,000 years apart.

The first article details some of the facts about the overall effect, while the article in the quote has a rough outline of the Chesapeake Bay crater - seems that most of the area around there would have gone bye-bye...