Two 305 m cored sections from the Northwest Florida continental shelf contain a nearly complete record of late Neogene hemipelagic sedimentation. One of the sites, south and east of De Soto Canyon, is isolated from terrigenous sediment except for sediment transported in suspension. This site contains a continuous record from the late Miocene to the Recent. The second site, on the western rim of De Soto Canyon, is more expanded and continuous from the late Pliocene to the Recent. A hiatus separates the late Pliocene from the middle Miocene. Six prominent nannofossil biohorizons were recognized within the Pleisocene, seven within the Pliocene, and three within the Miocene; in addition one biohorizon marks the base of the Pleistocene and another the base of the Pliocene.