Large tombs for pharaohs have been found at Abydos and Naqada. There are also cemeteries at Saqqara and Helwan near Memphis. These had buildings of wood and mud bricks, with some small use of stone for walls and floors. Stone was used for making ornaments, vessels, and sometimes for statues. Tamarix – tamarisk, salt cedar was used to build boats such as the Abydos Boats. They invented the ﬁxed Mortise and tenon joint. A ﬁxed tenon was made by shaping the end of one timber to ﬁt into a mortise (hole) that is cut into a second timber. A variation of this joint, using a free tenon, became one of the most important features in Mediterranean and Egyptian shipbuilding. It joined two pieces of wood by putting a separate tenon into a hole (mortise) of the same size cut into each piece.