On the spectrum of non-Denniston maximal arcs in PG(2,2h)

In 1969, Denniston gave a construction of maximal arcs of degree n in Desarguesian projective planes of even order q, for all n dividing q. Recently, Mathon gave a construction method that generalized that of Denniston. In this paper we use that method to give maximal arcs that are not of Denniston type for all n dividing q, 4<n<q/2, q even. It is then shown that there are a large number of isomorphism classes of such maximal arcs when n is approximately q.