  We prove there are exactly 16 arithmetic lattices of hyperbolic 3-space which
are generated by two elements of finite orders p and q with p,q at least six.
We also verify a conjecture of H.M. Hilden, M.T. Lozano, and J.M. Montesinos
concerning the orders of the singular sets of arithmetic orbifold Dehn
surgeries on two bridge knot and link complements.
