Panhole

A panhole is a depressed, erosional feature found on flat or gently sloping rock. Panholes are the result of long-term weathering and are generally seen on bedrock or very large blocks of rock. Similar terms are gnamma (Australia), opferkessel (German, roughly “sacrificial basin”), “armchair hollows”, weathering pans (or pits) and solution pans (or pits). Other German names include kamenitza and kamenica. In Spanish they are tinajita. In Portuguese and Galician are called pias.