When the Arnold Arboretum declined to finance a return expedition, Rock found sponsorship from the National Geographic Society to make a number of trips to southwest Sichuan to explore both the Konkaling range and Minya Konka (Mount Gongga). The latter is among the highest mountains outside of the Himalayas and was particularly difficult of assess, not least because of the purported hostility of the local tribes. Rock approached closer to Minya Konka than any other Westerner and with characteristic romantic exaggeration declared it to be higher than Everest, although at the time he was not alone in this wishful miscalculation. During these explorations, Rock based himself in the lama kingdom of Muli, which he had first visited in 1924. Another small kingdom that he often visited, also in southwest Sichuan, was Yongning on the beautiful Lugu Lake, center of the Mosuo people. These explorations produced a series of articles for the National Geographic magazine, although the editors were hard pressed to reshape them, much to his annoyance, for their more popular readership and to off-set Rock's propensity for accumulative detail over coherent presentation. Nonetheless he published a significant number of articles on little known areas and exotic peoples and customs of Western China accompanied by his excellent photographs.