Kerogen is the most abundant form of organic carbon on the earth and plays a very important role in the formation of hydrocarbons. In view of its vast abundance and importance, relatively little is known about its origin, method of formation or structure. Certain kerogens are known to have been formed from the remains of algae, bacteria, diatoms, fungi, and other microorganisms. In an attempt to get more information on these types of kerogens, we have isolated the insoluble organic matter of a recently-deposited algal mat from Laguna Mormona, Baja California. It has been isolated using techniques similar to those used in the isolation of kerogen from ancient oil shales and sediments. The kerogen-!ike residue from the algal mats has been exhaustively extracted to remove soluble lipid material and divided into two portions, one of which was saponified. The residues were further degraded by stepwise alkaline potassium permanganate oxidation. The major oxidation products identified included: αω-dicar-boxylic acids (range C8-C11). normal mono-carboxylic acids (range C110-C31); isoprenoid acids (range C11-C20); and mono-methyl branched acids (range C12-C18). The initial oxidation products were dominated by normal mono-carboxylic acids but with increasing time of oxidation the αω-dicarboxylic acids dominated