Oak Island, N. S., Sept. 16.—Oak Island's soil, reputed to hide Captain Kidd's fabulous treasure, yielded up an unexpected discovery yesterday. Earth fit from a cliffside, exposing an old Indian grave the age of which was estimated at 350 years. The grave evidently held a chief or some Mic-Mac or other high rank, for the warrior’s arms had been buri ed with him. The copper weapons were well-preserved in their birchbark sheath. The Indian’s skeleton was in ‘a good state of preservation.