Minor internal sedimentary structures in the uppermost layer of cored sediments are described and distribution of types is mapped for Sabine Lake, a lake estuary in southeastern Texas and southwestern Louisiana. Terminology and criteria of identificatiin are adapted from the study of Gulf of Mexico sediments by D. G. Moore and P. C. Scruton (1957), except that the term 'mixed structures' has been substituted for 'mottled structures' to avoid confusion with color. Mixed structures are the dominant type in Sabine Lake; fine homogeneous structures are next most prevalent, occurring along the southwest shore. Coarse and fine homogeneous, regular-layered, and irregular-layered structures occur in small areas. Possible formation processes are discussed.