THE COKE OVENS, looking north from overlook beneath Artists Point. A set of north-south joints has allowed erosion of the Wingate Sandstone to proceed more rapidly along these zones of weakness and has helped create the four ovens shown. Weathering away of the protective caprock of the overlying Kayenta Formation has produced rounded tops on all but the left-hand shaft, which is still protected by the Kayenta. Note alcoves and arches in cliff of the Wingate beyond, the formation of the one on the right having been aided by removal of the underlying soft Chinle Formation. Bench covered by piñon and juniper above Wingate is resistant thin-bedded Kayenta Formation. Cliff above the bench is the Slick Rock Member of the Entrada Sandstone. The Coke Ovens were named from their resemblance to the beehive-shaped brick ovens formerly used to convert bituminous coal into coke for smelting iron. (Fig. 11)
Many of the cliff walls of the Wingate are vertical, some even overhang, yet in some places the slopes are gentle enough to hold talus and to be climbed ([fig. 12]). Why is this? The answer to this question is given in a later section on “Canyon Cutting.”
Arches or shallow caves weathered out of some cliff faces of the Wingate, particularly where the underlying Chinle Formation has been partly scoured away. Although there are no large caves within the Monument, there are three in a row along the road 3 miles west of the Glade Park Post Office. One of these was inhabited until 1958 ([fig. 5]).
Many of the cliff faces of the Wingate are darkened or blackened by desert varnish—a natural pigment of iron and manganese oxides, silica, and clay.[19]
Dinosaurs left their footprints in the sands of the Wingate in parts of the Colorado Plateau, but no tracks or fossils have yet been found in this formation in or near the Monument.
The Rains Came
The arid climate of Wingate time was followed by a wet period, when streams from the northeast gradually covered the sand dunes with mud, sand, and some gravel. The sand and gravel of the stream channels were cemented into hard sandstone and conglomerate, and the mud of the flood plains hardened into red and purple siltstone and mudstone. The resulting Kayenta Formation makes up the bench between the two cliffs upon which the Visitor Center, campgrounds, and most of scenic Rim Rock Drive were built. Here, nature was kind, for this gently sloping bench was an ideal place to build the road from which to look down into the deep chasms. The Kayenta also caps the broad mesas between the canyons. It is about 350 feet thick in eastern Utah, only 45 to 80 feet thick in the Monument, and it is absent altogether not far east of the Monument. The reasons for the eastward thinning and ultimate disappearance of the Kayenta and some younger rocks are given in the [next section].
