Joining Dry Rock?

[fio1022]

I want to join to pieces of rock together to form a bridge.
Two DRY pieces on bench.
Dowels,epoxy putty???
What would be the best and most solid and secure way to do this?

[dzfish17]

I know alot of people use epoxy but I just used the E-marco 400 mortar from marcorocks to glue 2 rocks together. After letting the mortar dry for an hour I could not pull them apart.