The Question of Primordial and Cambrian/Taconic: Barrande and Logan/Marcou The Question of Primordial and Cambrian/Taconic: Barrande and Logan/Marcouv. 12No. 2111–120Yochelson, Ellis L. 1993. "The Question of Primordial and Cambrian/Taconic: Barrande and Logan/Marcou." Earth Sciences History, 12, (2) 111–120.More...ID: 95261Type: articleKeywords: NMNH; NH-Paleobiology; Annals-Import