The Company prospered until 1886. About that time, well-to-do families from the large cities began to build summer homes on the beautiful shores of Westbrook and they objected to the odor from the oil and guano factory. The summer residents finally succeeded in having the operation closed by law." Salt Island is also home to a number of kinds of animals, being watched over by the Stewart B. McKinney National Wildlife Refuge. Some parts of the island are not accessible due to wild seabird habitats. The indigenous animals that can be found on Salt Island include channeled whelks, Atlantic horseshoe crabs, common periwinkle, North American spider crabs, giant hermit crabs, terns, and oystercatchers. The island is also known for its strange rock formations. The rocks are carved from constant wave splashing and the changing of the tides. The rocks are short and almost resemble waves of the ocean. They can be touched but if not careful, you will cut yourself due to the intricate edges on the rocks from hundreds of years of formation.