I construct a quasianalytic field $\mathcal F$ of germs at $+\infty$ of real
functions with logarithmic generalized power series as asymp\-totic expansions,
such that $\mathcal F$ is closed under differentiation and $\log$-composition;
in particular, $\mathcal F$ is a Hardy field. Moreover, the field $\mathcal F
\circ (-\log)$ of germs at $0^+$ contains all transition maps of hyperbolic
saddles of planar real analytic vector fields.