We report the results of a series of shock transit time measurements in single-crystal olivine (San Carlos peridot) designed to assess any orientation dependences over the pressure range of 100--200 GPa. Each of the four shots included a specimen oriented normal to (100), one normal to (010), and one normal to the bisector of these two directions (approximately (120)), with time intervals measured by pin detectors (three per specimen). This third, oblique, orientation was chosen to maximize shearing along the closest-packed (100) planes. By analogy with the restacking model for the olivine-spinel transition, shear stresses promoting a pervasive (100) <010> system of stacking faults might facilitate the breakdown of the olivine structure, aiding the transition to the high-pressure phase and increasing the final shocked density. The Hugoniots of the three orientations were found to be coincident within experimental error, a conclusion at variance with earlier results obtained with synthetic forsterite which suggest that the compressibility along the b axis is significantly greater than along the a or c axes. Possible explanations for this discrepancy include experimental errors and a dependence of the high-pressure state on the orientation of the shock and the composition of the olivine. A softening of the Hugoniot beginning at approximately 150 GPa was found and may reflect melting or a change of the decomposed mixture of solid phases.