The Collaborative International Dictionary of English v.0.48:
Marly \Marl"y\, a. [Compar. Marlier; superl. Marliest.] Consisting or partaking of marl; resembling marl; abounding with marl. [1913 Webster]WordNet (r) 3.0 (2006):
marly adj 1: of or relating to or resembling or abounding in marl