Third-day road log: From Carlsbad to Dark Canyon, Last Chance Canyon, Sitting Bull Falls, Rocky Arroyo and return tp Carlsbad
— Jim W. Adams, David W. Love, and John W. Hawley

Today's tour traverses Permian basinal, shelf-edge, shelf-crest, inner-shelf and evaporite-shelf facies. It provides a cross section from the eroded edge of the Ochoan evaporite complex of the Delaware basin across the mid-late Guadalupian reef and backreef dolomites and evaporite/clastic red beds to the early Guadalupian margin and slope complex in Last Chance Canyon. Recently developed sequence-stratigraphic concepts provide new interpretations of these classic localities. The return to Carlsbad traverses the transition from evaporite shelf to dolomitized shelf crest in Rocky Arroyo and domal Tansill and Yates draped over underlying reef mounds.

The route heads west from Carlsbad up the lower segment of Dark Canyon across the eastern part of the Cueva Escarpment and northeastern prong of the Guadalupe Mountains. Stops and optional stops allow examination of the reef, shelf edge and shelf crest facies. The route then continues westward on NM137 and Eddy-409, traversing the low-relief, erosional Seven Rivers Embayment west of the cuestas of Azotea Mesa to Last Chance Canyon, cut across the northwest-trending Huapache monocline on the east flank of the northern Guadalupe Mountains. The lunch stop at Sitting Bull Falls provides the opportunity to see the highly scenic canyon as well as major active and inactive travertine deposits. Afternoon hikes and optional stops in Last Chance Canyon allow examination of upper San Andres depositional sequences with siliciclastic and carbonate facies reflecting lowstand, transitional and highstand systems tracts. After retracing the route east across the Seven Rivers Embayment, the tour skirts the northwest sides of many prongs of Azotea Mesa to the Seven Rivers Hills and Rocky Arroyo. The route descends eastward along Rocky Arroyo and its distal fan toward the Pecos River and US-285. Optional stops along Rocky Arroyo allow examination of abrupt facies transitions from evaporite shelf to dolomitized shelf crest and details of eolian sandstones. The tour then returns to Carlsbad past the domal Avalon and Ocotillo Hills. The final stop allows examination of the Tansill Formation near its type locality in the Carlsbad Springs area.