Recently Feldman et al (1984), used ISEE-3 data to analyze variations in charged particle and magnetic field characteristics near plasma sheet boundaries in the distant magnetotail and they demonstrated that several of the crossings had the properties of slow mode shocks. Here we discuss ISEE-3 plasma wave measurements at two of these crossings, and show that all conventional characteristics of fast collisionless shock spectra are present. Upstread (lobe side) electron plasma oscillations are detected in association with electron heat flux enhancements, and pronounced spectral peaks at lower frequencies are found within the shock layer.