First-day road log, trip 4, from Washington Ranch to Dark Canyon, Mosley Canyon, Queen Highway (NM 137), Queen, Klondike Gap, and Cottonwood Cave
— Lewis Land, David Love, and Victor Polyak

Trip 4 of the first day of the conference diverges from trip 1 at the junction of CR 408/Dark Canyon Rd with the Queen Highway, after having examined Capitan Reef and backreef exposures at the first three stops in Dark Canyon. From here trip 4 continues south across the Seven Rivers Embayment into the high Guadalupe Mountains to visit Cottonwood Cave, which is formed in Seven Rivers dolomite near the contact with the overlying basal Yates sandstone. The hike from the parking area to the mouth of Cottonwood Cave provides impressive vistas of Black Canyon, where the Yates-Tansill contact is well-exposed in Canyon walls. Cottonwood Cave itself contains some of the largest and most spectacular cave formations in the Guadalupe Mountains outside of Carlsbad Cavern itself.