The paper describes the effect of time and pressure on liquid product yields when Green River shale was exposed to supercritical methanol-water at 400°C and then extracted with benzene-methanol. Reaction times between 1 second and 34 minutes were studied as were pressures between 1800 and 5200 psi. Maximum yields of liquid product were obtained after a methanol-water treatment time of about 34 minutes. Presssure did not have a significant effect on product yields. Chemical characterization of Selected liquid products is reported and shows that the product composition varies with time. Exfoliation of shale also increases with treatment time. This phenomenon is discussed and illustrated.