  The atoms of the Schanuel topos can be described as the pairs $(n,G)$ where
$n$ is a finite set and $G$ is a subgroup of $\operatorname{Aut}(n)$. We give a
general criterion on an atomic site ensuring that the atoms of the topos of
sheaves on that site can be described in a similar fashion. We deduce that
these toposes are locally finitely presentable. By applying this to the
Malitz-Gregory atomic topos, we obtain a counter-example to the conjecture that
every locally finitely presentable topos has enough points. We also work out a
combinatorial property satisfied exactly when the sheaves for the atomic
topology are the pullback-preserving functors. In this case, the category of
atoms is particularly simple to describe.
