A conundrum that would tickle my (geologist) dad no end was that some of the earlier estimates of the age of the universe were lower than some of the older rock

A conundrum that would tickle my (geologist) dad no end was that some of the earlier estimates of the age of the universe were lower than some of the older rocks found on the earth. The article mentions red-shift of galaxies, it allows us to estimate their speed. One of the older scientific estimates of the age of the universe was based on "reverse" extrapolating those values.