the beachcombing lifestyle is associated with coastal shell-middens that sometimes accumulate over many hundreds if not thousands of years. Evidence at Klasies River Caves in South Africa, and Gulf of Zula in Eritrea, show that a beachcombing option is one of the earliest activities separating anatomically modern human Homo sapiens from the ancestral subspecies of Homo erectus. Modern usage Many modern beachcombers follow the "drift lines" or "tide lines" on the beach and are interested in the (mostly natural) objects that the sea casts up. For these people, "beachcombing" is the recreational activity of looking for and finding various curiosities that have washed in with the tide: seashells of every kind, fossils, pottery shards, historical artifacts, sea beans (drift seeds), sea glass (beach glass), driftwood, and messages in bottles. Items such as lumber, plastics, and all manner of things that have been lost or discarded by seagoing vessels will be collected by some beachcombers, as long as the items are either decorative or useful in some way to the collector. (However, this usually does not include the great bulk of marine debris, most of which is neither useful nor decorative.) Edmund James Banfield is an example of the modern beachcomber in his residence on Dunk Island in the early twentieth century where he studied and wrote about the vegetation, bird and sea life of the island. Sophisticated recreational beachcombers use knowledge of how storms, geography, ocean currents, and seasonal events determine the arrival and exposure of rare finds.Chuck and Debbie Robinson, The Art of Shelling Old Squan Village Publishing (1995) 22–23 They also practice eco-conservation and do not kill mollusks for their shells, dig holes in the sand, or gouge cliff faces for fossils or reefs for coral specimens. Many beachcombers serve as excellent stewards of the seashore, working with government agencies to monitor shore erosion, dumping and pollution, and reef and cliff damage, etc. Recognized beachcomb experts today include oceanographer Curtis Ebbesmeyer (Flotsametrics and the Floating World); eco-educator Dr. Deacon Ritterbush (A Beachcomber’s Odyssey); sea glass experts Richard LaMotte (Pure Sea Glass) and C.S. Lambert (Sea Glass Chronicles); geologist Margaret Carruthers (Beach Stones); shell specialists Chuck and Debbie Robinson (The Art of Shelling), and zoologist Dr. Blair Witherington and Dawn Witherington, (Florida's Living Beaches: A Guide for the Curious Beachcomber). Log salvage Along the coast of British Columbia in Canada, beachcombing or log salvage is the occupation of retrieving