322 J. P. Iddings — Columnar structure in the 



renowned for its large vertical columns, which have attracted 

 crowds of sight-seers from the immediate vicinity. While 

 these columns are very fine examples of what is commonly 

 met with on a smaller scale in many other localities, the chief 

 geological interest is centered in the curving and radiating 

 columns of smaller size into which the upper part of the mass 

 is broken. A general view of this quarry is given in the ac- 

 companying sketch, Plate IX, made from photographs taken by 

 the writer in May, 1884, and subsequently ; it therefore exhibits 

 some features which have been removed. At the southern end 

 of the quarry, left end of the sketch, rise large massive columns 

 from three to four feet thick and thirty feet high. They differ 

 in the number of sides, having four, five or six. The faces of 

 parting are not plane, but warped, giving a wavy form to the 

 columns. These columns diminish in height toward the north, 

 their breadth remaining constant, and are overlaid by long 

 slender ones, eight or ten inches thick, which meet them at 

 different inclinations. The main mass of these slender columns 

 converge toward a center at the top of the cliff about 90 or 

 100 feet above the floor of the quarry, which is only a few feet 

 above the beds of sandstone. Here they extend from top to 

 bottom and slope off to the north where they again lie upon 

 the tops of thick vertical columns like those to the south. 

 These stretch for a hundred yards farther north and differ in 

 height from fifteen to thirty feet, being highest near the north- 

 ern end of the quarry. 



Upon closer inspection it is seen that the tops of the large 

 vertical columns taper off and curve over on one another in a 

 direction away from the center of convergence of the overly- 

 ing columns, the upper and lower columns blending along the 

 line of junction. At the southern end of the central mass the 

 slender columns are nearly horizontal ; to the left of these are 

 slender vertical ones joining the first along a line inclined at 

 about 45°, along this they blend in the same manner as at the 

 junction of the upper and lower ones. A little farther to the 

 left, the system of slender vertical columns comes in conjunc- 

 tion with the larger vertical ones. The central mass of small 

 columns is further seen to converge to more than one focus, 

 three distinct ones lying near the face of the cliff and others 

 having been situated a little in front of it. These slender col- 

 umns are not straight except near the surface where they are 

 in groups of vertical prisms, from which they curve gradually 

 to an almost horizontal position. 



Above the heavy columns to the north the small ones lie at 

 various angles; those to the extreme right of the central mass 

 are partially exposed in nearly horizontal position, their dis- 

 tinct forms losing themselves in a confusion of cracks, out of 



