WHILST studying the Bibette Head Granite, the writer had occasion to devote a certain amount of attention to the rocks with which it is in contact. In the region under consideration, these are essentially of dioritic type. The Orbicular Diorite was first found in a small embayment forming part of the west side of Corblet's Bay. It was found later in a less well developed fashion, at Saye Bay. It is quite possible that extended search would prove the presence of more. For the most part the orbicules are widely scattered, but a boulder was found at the Corblet's Bay locality which shows several associated with inclusions of a more basic rock. This boulder is now in the Sedgwick Museum, Cambridge.