A thick quasi-parallel bow shock structure was observed for ϑnB≲10¿, &sgr;?0.3 and ML?4 on February 14, 1969, with field and particle detectors of both Heos 1 and Ogo 5. The typical magnetic pulsation structure was at least 1--2 RE thick radially and was accompanied by irregular but distinct (average) plasma distributions characteristic of neither the solar wind nor the magnetosheath. Waves constituting the large pulsations were polarized principally in the plane of the nominal shock and therefore also in the plane perpendicular to the average interplanetary field. The solar wind was relatively unaffected in bulk velocity in the pulsation structure but was moderately thermalized, and its spectra showed a high-energy tail. There appeared to be a separate 'interpulsation' regime occurring between bursts of large amplitude oscillations. This regime was magnetically similar to the upstream wave region but was characterized by disturbed plasma flux and enhanced noise around the ion plasma frequency. The shock structure appeared to be largely of an oblique whistler type, probably complicated by counterstreaming high-energy protons. Evidence for fire hose instability base structure was weak at best and probably negative.