The four arches just described are of the foundation series of the eastern base, and cover laccolites of unknown depths. Higher in the strata, and at the same time absolutely higher, is a second series, which to a certain extent overlap them. The Bowl Creek encroaches on the G laccolite; the Jukes, on the Dana and on the Bowl Creek; the H laccolite, on the Crescent; the Peale and Scrope, on the Maze. [Illustration: FIG. 46.—Cross-section of the Bowl Creek Arch. _c_, _c_ marks the water level of Bowl Creek; _l_, the Bowl Creek Laccolite; _a_, _a_, Shales; and _s_, the Gryphea Sandstone. Scale, 1 inch = 1,000 feet. ] _The Bowl Creek arch_ is so masked by the overlapping Jukes laccolite, and by the encroachment of certain large dikes, that its general form and proportions are not known; but it is laid bare at one point in a fine natural section. Bowl Creek crosses it near the center, and in the walls of the cañon are exhibited two hundred feet of the laccolite, together with two hundred and fifty feet of superjacent beds. The curve of the strata is unbroken by faults or dikes, and carries them below the level of the creek at each end of the cañon. Next above the trachyte lies a clay shale which has been baked to the hardness of limestone. It is one hundred feet thick, and is more or less altered throughout, as is also the sandstone which overlies it. The extent of the metamorphism indicates that the trachyte mass by which it was produced is not a mere sheet, but is the body of the laccolite itself. _The Jukes laccolite_ encroaches upon the G, the Dana, and the Bowl Creek arches, and is superior to them all; it may be said to stand upon them. The trachyte has a depth of only one thousand feet, but it lies so high with reference to the general degradation that it is a conspicuous feature of the topography. The edges of the laccolite are all eaten away, and only the central portion survives. All of its faces are precipitous. The cover of shale or sandstone has completely disappeared, and the upper surface seems uneven and worn; but a distant view (Figure 47) shows that its wasting has not progressed so far as to destroy all trace of an original even surface. The eminences of the present surface combine to give to the eye which is aligned with their plane the impression of a straight line. The hill is loftier than the laccolite, for under the one thousand feet of trachyte are five hundred feet of softer rock which constitute its pedestal, and by their yielding undermine the laccolite and perpetuate its cliffs. [Illustration: FIG. 47.—Profile of the Jukes Butte, as seen from the northwest. ] _The H laccolite_ is not well exposed. It lies on one edge of the Crescent arch and is covered by the Henry’s Fork conglomerate. [Illustration: FIG. 48.—The Peale Laccolite exposed in natural cross-section. _a_, _b_, _c_, _d_, and _e_ are intrusive masses of trachyte. _H_ is the Henry’s Fork Conglomerate. ] [Illustration: