On April 6, 1980, Adam Zertal, Ph.D, Prof. Of Archeology, Univ. of Haifa was doing a formal archaeological survey of the traditional lands of Manasseh and discovered a Hebrew Altar that dated to 1250 BC. Using pottery to date the site Zertal said: "More important, however, is that they [the pottery] fix a date for the construction of the altar - approximately 1250 B.C.E."
The site at Mt. Ebal had two occupation levels. Zertal calls the older occupation "level II" which he dates 1300 BC and the younger level I to 1250 BC.If this site is no older than 1300 BC, then none of it could be built by Joshua, because the exodus took place in 1400 BC. However this is a Hebrew altar built during the time of Deborah the Judge and underneath we believe is the actual altar of Joshua that should be dated to 1400 BC since a scarab from Tuthmosis III was found but wrongly dated to 1250 BC.
We agree that there are clearly two occupation levels. The rectangular altar we see today was built about 1250 BC. The 6.5 foot circular stone structure with burnt kosher bones inside is located directly beneath the rectangular altar and was built about 1400 BC by Joshua.