ation points. Alternatively, a list with two elements: the first is
a character vector with node names from phy to calibrate; the second is a numeric
vector with the corresponding ages to use as calibrations.</p></dd>


<dt>age_distribution</dt>
<dd><p>A character string specifying the type of calibration.
Only "fixed" and "uniform" are implemented for now.</p><dl><dt>fixed</dt>
<dd><p>The age given in ncalibration will be used as fixed age.</p></dd>

<dt>lognormal</dt>
<dd><p>The age given in ncalibration 