Black shales of the Pennsylvanian System of west central Illinois were examined in a paleoecologicalstudy using micro-radiographic (X-ray) and photographic techniques. Over 80 different fossil varieties were tentatively identified, including a proposed new conodont species, Metalonchodina magnidentatus, Peters, a small Pennsylvanian Onychophore(?), and several freshwater Algae. Study methods included gross and macrophotography, microscopic examination of thin shale chips, and photomicrographic inspection of X-rays of shale samples. The radio-photomicrographic technique supplemented and bypassed the usual practice of crushing and chemically disaggregating the shale to extract the microfossils. Structural details could be observed in fossil elements in X-ray negatives rotated on the stage of the polarizing microscope set at or near crossed nicols. Cyclical deposition was indicated by the structural details of the shale as well as by the virtually mutually exclusive occurrence of foraminifera and conodonts in successively alternating bedding planes and black shale matrix. Rapid transport and burial was implied from the following observations: Orbiculoidea shells packed into lenses up to one inch thick; microlaminations apparently interrupted by small coal balls; and the distorted bedding, both at the bottom and the top of the shale member. All of the reported observations strongly support the Biblical tidal interpretation of fossil deposition and burial.