In Vincent et al. (Reference Vincent, Carter, Lavrishchev, Rice, Barabadze and Hovius2010) the boxed key shown on Figure 2 includes the following definition:
![\begin{equation}
\begin{array}{*{20}l}
{{\rm Symbol}\,{\rm diameter}} & {= {\rm AFT}\,{\rm age}\,{\rm or}\,{\rm lag}\,{\rm time}\,({\rm Ma})} \\
\, & {\approx {\rm erosion}\,{\rm rate}\,({\rm km}\,{\rm Ma}^{- 1})} \\
\end{array}\end{equation}](https://static.cambridge.org/binary/version/id/urn:cambridge.org:id:binary:20180419074309567-0221:S0016756810000865:S0016756810000865_eqnU1.gif?pub-status=live)
The symbol diameter is inversely proportional to the AFT age or time lag and proportional to the erosion rate; the definition should therefore read:
![\begin{equation}
\begin{array}{*{20}l}
{{\rm Symbol}\,{\rm diameter}} & {\propto 1/{\rm AFT}\,{\rm age}\,{\rm or}\,{\rm lag}\,{\rm time}\,({\rm Ma})} \\
\, & {\propto {\rm erosion}\,{\rm rate}\,({\rm km}\,{\rm Ma}^{- 1})} \\
\end{array}\end{equation}](https://static.cambridge.org/binary/version/id/urn:cambridge.org:id:binary:20180419074309567-0221:S0016756810000865:S0016756810000865_eqnU2.gif?pub-status=live)
(see scale bars below)