A simple kinematic model is used to illustrate the vertical motions of rocks during convergent deformation and erosion at the surface. It is shown that rocks may move upward or downward in the crust, depending on the relative rates of erosion and thickening and depending on their initial depth in the crust. Exhumation during thickening can only occur if rapid denudation accompanies the thickening process. During homogeneous thickening with erosion that is elevation dependent, the initial depth from which rocks can be exhumed is only determined by the density distribution in the column and is independent of erosion or thickening rates. The maximum initial depth, from which rocks can be exhumed, is of the order of 30 km or less. There is therefore no conflict in the observation of synchronous exhumation and convergent deformation if the peak pressure of rocks is equivalent to no more than 30 km of burial. It is also shown that uplift (defined as vertical motion of the surface with respect to a reference level, for example the geoid) and exhumation (defined as vertical motion of rocks with respect to the surface) may follow different patterns in time and that the difference between the two evolutions may be a useful indicator of the exhumation process. The model serves to emphasize the important differences between uplift and exhumation which are often not distinguished in the literature. ¿ 1998 American Geophysical Union