The molecular composition of bitumen (11 samples) and pyrolysis products of kerogen (7 samples) isolated from rocks from Upper Devonian deposits in the Pechora basin was studied in detail by gas chromatography and gas chromatography-mass spectrometry. The thermal maturity of the organic matter was low (0.4-0.6% R-o). The main source of the initial organic matter was marine phytoplankton represented by microalgal, cyanobacterial, and bacterial biota, and a considerable fraction of organic matter of terrigenous origin was found for several samples from the northern part of the basin. Kerogen was formed from the lipid components of the original organic matter, as is confirmed by high concentrations of n-alkyl structures in kerogen pyrolysis products: n-alkenes-1 and n-alkanes, as well as long-chain 2,5-dialkylthiophenes, n-alkylbenzenes, n-alkylnaphthalenes, and n-alkylbenzothiophenes. The fraction of sulfur-bound carbohydrate components in the kerogen composition was low, as was confirmed by low fractions of short-chain 2,5-dialkylthiophenes in the pyrolyzates. Isorenieratene derivatives in the aromatic fractions of the bitumen and kerogen pyrolysis products indicate photic, zone euxinia during sedimentation.