Sediment flux on transport-limited hillslopes is well known to vary nonlinearly with slope, diverging as the angle of stability is approached. To date, however, no study has validated the precise form of the nonlinear slope-dependent transport model over geologic time scales in a non-steady-state landform. In this paper, we show how cinder cones can be used to validate the nonlinear transport model using Lathrop Wells cinder cone in Nye County, Nevada, as a type example. Cinder cones are well suited for this purpose because they can be radiometrically dated and their angles of stability can be constrained by measurement of subsurface contacts between primary fallout and overlying colluvial deposits reworked from upslope. Forward model results with a generalized, nonlinear transport model characterized by diffusivity, κ and nonlinear exponent, n, show that the evolution of the cone rim and base are most sensitive to κ while the cone midpoint is most sensitive to n. Analyses of the full cone shape, therefore, permit the two model parameters to be independently inferred if the cone age and angle of stability are independently known. Results for Lathrop Wells imply that n = 2 in the generalized, nonlinear transport model, which is consistent with Roering et al.'s (1999) widely used form of that model.