  We consider singularities of frontal surfaces of corank one and finite
frontal codimension. We look at the classification under left-right-equivalence
and introduce the notion of frontalisation for singularities of fold type. We
define the cuspidal and the transverse double point curves and prove that the
frontal has finite codimension if and only if both curves are reduced. Finally,
we also discuss about the frontal versions of the Marar-Mond formulas and the
Mond's conjecture.
