We have measured the thermal conductivity ε and the heat capacity per unit volume ρcp of highly pure C70 in the temperature interval 100-450 K under pressures up to 1 GPa. Anomalies indicating freezing of uniaxial molecular rotation were observed in λ and ρcp upon both cooling and increasing pressure. The phase boundary for this transition has an approximate slope dT/dp = 70 K Gpa-1. The temperature and pressure dependence of λ indicate a substantial amount of structural defects in the sample and strong metastability effects.