Named after the 17th century French theologian, Denis Petau, this 188-km wide circular formation on the southeastern bank of Mare Fecundidatis is one of a handful of craters characterized with a fractured floor which, in this case, emanates from the central peak and terminates on the southwest periphery. Measuring approximately 80 km in length and 2 km in width, the rille is visible under good seeing conditions. Even more difficult to observe, however, is a second rille also emanating from the central peak and extending towards the north but which is significantly shorter in length. As indicated by the image below, the floor is riddled with various rilles emanating from the central peak and which generally point north; to the south of the peak, there appears to be a large aggregation of domes.