Abstract
Two brackish clay beds of different age are found along the lower reaches of the Chao Phraya River of Thailand. The older one is from 2 to 6m above M. S. L. forming a terrace surface, with the outcrop area 100 to 150km inland from the Gulf of Thailand, and an equivalent bed is also to be found at a level 11m below M. S. L. near the gulf coast. This older clay bed is assumed to be of upper Pleistocene age. The younger one extends over a broad area facing the gulf and forms a very flat plain 2m above M. S. L. This is dated post-glacial by C14 dating.
