There is a short animation here which shows how spits are formed .
This aerial view of the spit which is part of the St Joseph State park in Florida shows the typical features of parallel dune ridges at the recurved tip. and the image below from Flickr shows the seaward side of the spit looking north.
Mark turned inland at Port St Joe opposite the tip of the spit and very quickly left the coastal environment behind. Beaches quickly give way to forest in this part of Florida. As a state, Florida is well forested. It has 25,000 square miles of forest which is half of the state's area. The forests are in both private and state ownership producing 650 million cubic metres of timber and a huge number of timber products annually. Surprisingly (to me at any rate) Florida's highest value agricultural product is trees. Over $16.6 billion is infused into Florida's economy from the manufacturing and distribution of forest products each year.The first part of the route inland took Mark through many miles of commercial forest with evidence in places of clearfelling and reafforestation. As he approached Gaskins Still and Wewahitchka, the commercial forests gave way to the swamp natural forests on the floodplain of the Apalachicola river and its tributary the Chipola. And here are the second 'meanderings' - this time on the river itself...
After all these months of looking at rivers across the globe, I feel confident I can leave you to explain what you are seeing here! However, what you won't see from this altitude is that there are many small rafts on the river Apalachicola... They are floating bee hives and they are linked to a very unique product of the region - Tupelo honey! The town of Wewawitchika is the global centre of Tupelo honey production as explained here.... and here the website of the company who dominate production.
>Beyond Dead Lakes Mark meandered his way north toward the border with Georgia where he stopped last night just south of Lake Seminole at the town of Sneads. Lake Seminole was formed by damming the Chattahoochee and Flint rivers which flow into the lake from the north and east respectively. The Jim Woodruff lock and dam impounds the lake from which the main outflow is the Apalachicola river.