The following is adapted from my field notes on a research trip to San Salvador Bahamas.
North Point is made of eolianites which are made of wind deposits of calcium-rich sand from the island mainland. The wet carbonate turns sold. A crust (caliche) forms on the surface and the then rest solidifies. These dunes are less than 500 years old. My professor, Fred said that sometimes the crust of the eolianites breaks and then is filled with sand which cements. It is harder than the rest of the eolianites so while the rest erodes it stays behind. Off of North Point, there is a shipwreck of a gas tanker. Fred saw a grey catbird (Dumetella carolinensis).These birds are named after their cat-like meowing sounds. Non breeding birds can be found as far south as the Bahamas. We also saw white-tailed tropic birds (Phaethon lepturus). They have very elegant long whitetails. They can be found in Hawaii as well. They don’t build nests and instead lay eggs on the bare ground. I saw several really small hermit crabs, which are also called soldier crabs (Coenobita clypeatus) taking advantage of old snail shells. This crab is one of two species that is commonly sold as pets. They are both herbivores and scavengers.