At Lachish, Petrie found massive city walls, though he did not describe them in detail.[136] At Taanach, Sellin found a strong city wall, but did not attempt to trace it about the tell.[137] Schumacher devoted considerable attention to the city walls of Megiddo, a part of which were built of bricks.[138] At Tell es-Safi (Gath?) the outlines of the city walls were traced, as they were at Tell el-Judeideh.[139] At Samaria a part of the Roman wall of the time of Herod was found; lower down in the mound remains of a Babylonian wall (see 2 Kings 17:24), beneath which the excavators recognized the Hebrew wall.[140] City walls were found, too, at Bethshemesh,[141] but of especial interest to the student of the Bible are the walls of Jericho. Here, as at Megiddo, the walls were constructed in part of brick. They had an average thickness of 13 feet. The Canaanitish wall was traced around three sides of the mound. It was strengthened by occasional towers.[142] On the east, next to the spring, they had entirely disappeared. This must not be pressed into a confirmation of Josh. 6:20, that the walls fell down flat, for the later Israelitish wall has disappeared on that side of the mound also. Later, when in the days of Ahab the Israelites rebuilt the city (1 Kings 16:34), they did not place the wall on the old line, but enclosed a considerably larger space. This wall was constructed partly of bricks, but mostly of stone.[143] The walls of Jerusalem will be treated in Chapter XIII. At the northwest corner of the Canaanitish wall was a tower enclosed by two brick walls; the outer wall was a little more than 4 feet thick; the inner, about 10 feet. =3. The Stone Work.=--The kind of stones used in city walls varied with the circumstances and the degree of civilization. The walls of the stone age were naturally made of small undressed stones. The Amorites began the use of cut stone. Their blocks are often fairly smooth and regular. The Amorite wall of Gezer was made of more regular stones than the wall of the Egyptian period.[144] In the Israelitish and Jewish periods a stone with an embossed edge was often used. It is found in the wall of Nehemiah, excavated by Bliss,--a wall made of stones that some pre-exilic king had used before,--and appears also in the structures of Herod the Great. In the structures of Constantine and later Byzantine builders, this type of stone is replaced by a stone with a perfectly smooth surface--much more smooth than anything found in the early walls. This type of stone work continued through the crusading period; (see Figs. 253, 254.) While these types can be traced, their use was not altogether regular.[145]