Compressional wave phase velocity and attenuation have been measured in several high-porosity (20--26%) sandstones as a continuous function of frequency from 400 to ~2000 kHz. Samples include Massilon, Bera, and Boise sandstones and a synthetic fused glass bead samples all show negative velocity dispersion (velocity decreasing with increasing frequency) and attenuation (dB/m) increasing as the third to fourth power of frequency. These data are interpreted as evidence of scattering within the samples. Brine saturated rocks show positive velocity dispersion and attenuation increasing with a first to second-power frequency dependence. These data are interpreted as evidence for a local fluid-flow loss mechanism. Fused glass beads show no indication of flow related losses.