Fifty-eight samples of lake sediments from seventeen profiles distributed among twelve playa lakes located in northeastern California, southeastern Oregon and northwestern Nevada were analyzed. The samples were treated with distilled water to find the amount of watersoluble salts; with cold hydrochloric acid (1-1) to determine the amount of acid-soluble matter; and were subjected to elutriation to determine the amounts of sand-silt and silt-clay materials. The water-soluble salts are always of low content (as much as 10 per cent, but rarely over 5 per cent); the acid-soluble matter is variable in amount (20-74 per cent), rarely dropping below 20 per cent; and the sand-silt and silt-clay fractions show great variation from almost pure sands to clays with scarcely any sand in them. Some of the clays are laminated, but the laminations do not appear to represent varves. Crust materials commonly observed on dry lake beds were not found in the sediments.