This paper attempts a time-stratigraphic correlation with the available data on maturity of vitrinite for some selected wells in the Broach Depression of the Cambay Basin. Applying some modifications in the kinetic model of first-order reaction, the change in R(o) with time and temperature has been found to follow the equation: In [In (K＇R(o)) ] = ln (At) - E/RT where T is the temperature, t the time, and R(o) the reflectance; A, E and R are parameters in the Arrhenius equation. This principle is used to correlate three key wells on the western rising flank of the Broach Depression for evaluating time planes. The results have been found to be in consonance with the paleontological data.