Day 3 Cubero to Seboyeta to L-bar Ranch
— Bonnie Frey, Shari Kelley, Fraser Goff, and Richard E. Kelley

On Day 3 (Fig. 3.1), we visit the east side of Mt. Taylor. The Jackpile Member of the Morrison Formation will feature prominently at Stop 1, where we will discuss the age of the unit and consider the depositional environment of Morrison, Dakota and Mancos members, several which have type sections in the vicinity, and their relationship to the Dakota “main body” described west of Grants. Our route takes us into the Laguna Mining Subdistrict (Color Plate, page 90), where we will drive past the Jackpile Mine, which was the world’s largest uranium mine when it was in operation from 1953 to 1982, producing 26.6 million short tons of ore (McLemore et al., 2021, this volume). We will stop at the reclaimed L-Bar mill and mine site that, during its lifetime, capitalized on uranium mineralization in the Morrison Formation. We will introduce two older volcanic features associated with Mt. Taylor, the Cerro Negro volcanic neck and a diatreme within Cretaceous sedimentary beds. Throughout the day we will remain near the scenic mesas associated with Mt. Taylor and within a landscape dominated by Mesa Chivato (“chivato,” Spanish for young male goat), a large volcanic feature that developed north and northwest of Mt. Taylor (Goff et al., 2019). The sites we are visiting on Day 3 are by permission of either the Pueblo of Laguna or the Seboyeta Land Grant.