Complex sentence: Chiapa de Corzo is also notable for a pottery sherd containing what is likely Epi-Olmec script--dated to as early as 300 BCE, this sherd would be the oldest instance of that writing system yet discovered.
Split into simpler sentences: Chiapa de Corzo is also notable for a pottery sherd containing what is likely Epi-Olmec script. Dated to as early as 300 BCE, this sherd would be the oldest instance of that writing system yet discovered.