The last major addition to the biblical text was a post-exilic (pre-3rd century BCE) source which Dr. Tzemaḥ Yoreh refers to as the "Bridger" or simply, 'B.' B supplements earlier layers of text with genealogies and popular myths, providing narrative bridges between distant story cycles. B's narrative additions often share a fantastic element rarely found in Biblical narrative, and are most likely later additions to their respective Pentateuchal frameworks.