About 1 mile farther northwest is a parking area (stop 23) from which a short walk to the north end of Fiery Furnace leads to a narrow slot between high fins (fig. 45), along which a short sandy trail leads to a recess along the southwest wall containing Sand Dune Arch (fig. 46). This hidden arch receives sunshine only near the middle of the day and is a delightful, shady place to rest. From the entrance to the slot leading to Sand Dune Arch, a trail goes half a mile north across an open field to Broken Arch, shown in figure 16. This field, which separates the Fiery Furnace and Devils Garden areas, is seen from the air in figure 12. [Illustration: Petroglyph figure] [Illustration: FIERY FURNACE, viewed northwest along park road about 1 mile northwest from stop 20. Fins and spires are of the jointed Slick Rock Member (fig. 12), but the top of the Dewey Bridge Member is seen to the right of the curve in the road. (Fig. 44)] [Illustration: TRAIL TO SAND DUNE ARCH, looking northwest away from arch, between towering fins of Slick Rock Member, at northwest end of Fiery Furnace. Southeast end of Devils Garden in distance. (Fig. 45)] [Illustration: SAND DUNE ARCH, in recess along southwest wall of narrow slot shown in figure 45. Slick Rock Member. (Fig. 46)] Salt Valley and Klondike Bluffs Before proceeding to the end of the paved road, let us take an unimproved side road, which turns south about a third of a mile beyond the last stop, in order to see more of Salt Valley and to visit Klondike Bluffs in the northwestern part of the park. After descending 2.3 miles of winding road we reach the normally dry bed of Salt Valley Wash, and turn abruptly to the northwest. For the next three-fourths of a mile the “road” is simply two tracks in the loose, sandy bed of the wash, which obviously should not be travelled when flooded or when there is even a hint of rain. In dry weather, however, this road may be travelled by ordinary passenger car. This stretch of the wash cuts through an intruded block of the Paradox Member of the Hermosa Formation consisting mainly of gray and brown gypsum, the common salt having been dissolved out by ground water. Such an intrusive block of salt-bearing rock is known to geologists as a diapir—not to be confused with the garment (diaper) worn by infants. From here on the road traverses a rather uninteresting stretch of valley north of Salt Valley Wash. Eleven miles from the starting point, the road reaches an intersection from which a side road leads southwestward three-fourths of a mile to a parking area at the foot of Klondike Bluffs, which form the south side of Salt Valley. From here, one may make a strenuous hike over a primitive trail about 1½ miles long to beautiful Tower Arch (fig. 47).