They used the repository's database to find specimens made of stuff—especially basalt, chert (of which the most familiar type is flint) and obsidian—that hominids had a penchant for working into tools before the development of bronze and iron.
他们使用该存储库库来查找由以下材料制成标本——尤是玄武岩、(中最常见类型是)黑曜——原始人在青铜铁出现之前就喜欢制作工具。