In a 1971 "Argosy" article, Robert Marx reported that Carl H. Holm, who was President (not "head geologist" as reported by Marx) of Global Oceanic, once a manager for North American Rockwell, a ship designer; and retired naval officer, stated that there was "little doubt" that the massive stone blocks were cut by people. The same article noted that he was part of an expedition sponsored by North American Rockwell that included Edgar Mitchell, the astronaut, as leader; Dimitri Rebikoff; and "a number of psychics from the Edgar Cayce Foundation." Others who consider the Bimini undersea formation to be man-made, as opposed to natural beachrock, are Joseph Manson Valentine, zoologist; Charles Berlitz, linguist; Greg Little, psychologist; R. Cedric Leonard, anthropologist; and Dimitri Rebikoff, French marine engineer. All claim to have investigated the formations in person, and claim to have observed more than one horizontal layer of blocks, at least in places. However, multiple layers of block can result naturally from systematic fracturing of sedimentary rock where multiple layers of sedimentary rock lie on top of each, as can be observed in the case of the tessellated pavement of Tasmania exposed at Eaglehawk Neck on the Tasman Peninsula. In his controversial book "1421: The Year China Discovered America" and its accompanying documentary, "1421: The Year China Discovered America?" amateur historian Gavin Menzies claimed that when Chinese admiral Zheng He's fleet was in the process of circumnavigating the globe in 1421-3, it stopped at Bimini - see 1421 hypothesis. According to Menzies, half of the fleet, under the command of admiral Zhou Wen, was caught in a hurricane near Bimini and built the Bimini Road from beach rock and the ships' ballast as a slipway to haul damaged junks ashore for refitting and repairs of damage caused by the hurricane. Sci Fi's "Quest for Atlantis: Startling New Secrets" followed several different groups researching possible locations for the legendary Atlantis, one of which focused on the Bimini Road. Greg Little led a team of researchers on a dive to recover objects at Bimini Bay. Little and his team reported the discovery of an entire second layer of square-cut rocks with similar dimensions beneath the stones of the Bimini Road. However, they have yet to formally publish in any detail the evidence and observations that demonstrate the presence of this underlying layer and the square-cut nature of its blocks.