The magnificent photographs taken by the Apollo 15 astronauts during their excursions upon lunar soil reveal that the Apennines of Hadley present a very evolved morphology demonstrating intense processes of degradation comparable to those phenomena which acted upon the earth's most ancient mountain chains, those which, for example, can be attributed to the caledonian orogenesis. The Apollo 15 photographs bear evidence that at least some of these mountains are formed by stratified rocks, which because of various considerations - being forced to exclude the existence of marine or alluvial sediments - one is inclined to consider pyroclastic.