binary representation of date and numeric

Hi,

what is the binary representation of 'date' and 'numeric' data?

I am using PQexecParam (C binding libpq-8.0.12) with binary export
switched on. From the three examples in C code the types 'int4', 'bytea'
and strings are covered, however nothing about 'date', 'numeric'.

If there is no documentation and I need to examine the sources, could
anyone point me to the needed files or sections?

Thank You

Felix