The carbohydrate content of 38 fossil specimens linens analyzed by a phenol-sulfuric acid method ranged from 4 to 900 ppm. The rock matrix associated with the fossils contained carbohydrates in the range 15 to 660 ppm. Absorption spectra of the colored carbohydrate degradation products, after reaction with phenol, verified the general chemical nature of the substances tested, and indicate that the fossils contain mainly hexose residues (lambda max 490 mu); in others, the carbohydrates are predominantly pentoses (lambda max 480 mu). In some instances the carbohydrate composition of the fossil differed from that of the matrix. The specimens of Protozoa, Mollusca, Arthropoda and plants studied have carbohydrate values in the general range of 50-300 ppm. Specimens of fossil Hydrozoa, Bryozoa, Brachiopoda, Annelida-rock, Cephalopoda, Echinodermata and Vettebrata contained a greater overall range in carbohydrates. Although the carbohydrate content of the sedimentary matrix associated with some of the fossil specimens equals or exceeds that of the fossil material there is no present evidence that the latter are contaminated by the carbohydrate materials from the associated matrix. In the present set of fossil specimens, although the values vary widely, the presumed neritic types average about the same as the littoral types in total carbohydrates. The matrix associated with the presumed littoral fossil specimens, however, averages somewhat higher than that in which the neritic types occur. Fossils from geosynclinal Paleozoic rocks studied typically contained more carbohydrates than associated matrix: Paleozoic fossils from shelf environments, however, contained less than the matrix. Mesozoic and Cenozoic fossils and matrix averaged more nearly similar in carbohydrates. No relationships were observed between carbohydrate contents and geologic age of the fossil specimens. Other rock samples of Precambrian to Jurassic age studied here for total carbohydrates as well as samples studied previously have values that fall in the general range of the fossil matrix. Algal-oolitic Jurassic reef limestones are among the lowest in carbohydrates of all samples examined. Proximity to a rhyolite sill had little apparent effect on carbohydrate values in Pennsylvanian shale and limestone. When Devonian shale samples were heated in nitrogen atmosphere maximum yield of total carbohydrates was obtained at about 175 degrees C; at 225 degrees C yield was O. Nine monosaccharides were separated chromatographically from a representative set of marine Devonian rocks containing phytal debris and two of the sugars were verified with enzymatic tests.