During the earlier half of 1918 Mr. San Ah Wing, a Chinese gentleman residing in Kuala Lumpur, sent me three concentrates of sand for examination. It was thought at first that they came from some part of the Federated Malay States, but the locality proved to be the Yong Choon district of the province of Kwang Tung, China. No information concerning the geology of this district was obtainable, but the association of minerals in the concentrates suggests that they were washed out of detritus derived from calcareous rocks.