Read this: Around 10,200 BC the first fully developed Neolithic cultures belonging to the phase Pre-Pottery Neolithic A (PPNA) appeared in the fertile crescent. Around 10,700 to 9,400 BC a settlement was established in Tell Qaramel, 10 miles north of Aleppo. The settlement included 2 temples dating back to 9,650. Around 9000 BC during the PPNA, one of the world's first towns, Jericho, appeared in the Levant. It was surrounded by a stone and marble wall and contained a population of 20003000 people and a massive stone tower. Around 6,400 BC the Halaf culture appeared in Lebanon, Israel and Palestine, Syria, Anatolia, and Northern Mesopotamia and subsisted on dryland agriculture.

What materials were used to build the wall around Jericho?
What is the answer? (If it cannot be answered, return "unanswerable")
stone and marble