Sefel Geophysical Ltd., Denver, Co No description specified. 1-2 (2 Records) Documents Archeological Survey of Sefel Geophysical Ltd.'s Seismograph Line No. L-84, Northern Moffat County, Colorado (1984) Cultural Resource Inventory and Avoidance of Eight Sefel Geophysical, Ltd. Seismographic Lines in Emery and Wayne Counties, Utah (1984)