The compressional wave velocity of rock in situ measured at four sites in the White Mountains of New Hampshire varies as a function of azimuth and is anisotropic. The anisotropy <(Vmax-Vmin)/Vmax>, which ranged from 18% to 42%, is attributed to two sets of cracks with different azimuths and with total crack density of order of 0.2 at each site. The anisotropy in velocity correlates only approximately with the orientation of mapped joints at each site.