The Bahamas Platform, which includes The Bahamas, Southern Florida, Northern Cuba, the Turks and Caicos, and the Blake Plateau, formed about 150 Ma, not long after the formation of the North Atlantic. The  thick limestones, which predominate in The Bahamas, date back to the Cretaceous. These limestones would have been deposited in shallow seas, assumed to be a stretched and thinned portion of the North American continental crust. Sediments were forming at about the same rate as the crust below was sinking due to the added weight. Thus, the entire area consisted of a large marine plain with some islands. Then, at about 80 Ma, the area became flooded by the Gulf Stream. This resulted in the drowning of the Blake Plateau, the separation of The Bahamas from Cuba and Florida, the separation of the southeastern Bahamas into separate banks, the creation of the Cay Sal Bank, plus the Little and Great Bahama Banks. Sedimentation from the "carbonate factory" of each bank, or atoll, continues today at the rate of about  per kyr. Coral reefs form the "retaining walls" of these atolls, within which oolites and pellets form.