We measure the Drell-Yan differential cross section [ital d][sup 2][sigma]/[ital dM] d[ital y][vert bar][sub [vert bar][ital y][vert bar][lt]1] over the mass range 11[lt][ital M][lt]150 GeV/[ital c][sup 2] using dielectron and dimuon data from [ital [bar p]p] collisions at a center-of-mass energy of [radical][ital s] =1.8 TeV. Our results show the 1/[ital M][sup 3] dependence that is expected from the naive Drell-Yan model. In comparison to the predictions of recent QCD calculations we find our data favor those parton distribution functions with the largest quark contributions in the [ital x] interval 0.006 to 0.03.
