GEOLOGICAL SUEVEY OF THE TERRITORIES. 115 



and the continual wear of the under side of the crust on the west side 

 has caused the margin to fall in, until an aperture at least 250 feet in 

 diameter has been formed, with walls or sides 20 to 30 feet high, showing 

 the laminse of deposition perfectly. The water is intensely agitated all 

 the time, boiling like a caldron, from which a vast column of steam is 

 ever arising, filling the orifice. As the passing breeze sweeps it away 

 for a moment, one looks down into this terrible seething pit with terror. 

 All around the sides are large masses of the siliceous crust that have 

 fallen from the rim. An immense column of water flows out of this 

 caldron into the river. As it pours over the marginal slope, it descends 

 by numerous small channels, with a large number of smaller ones si)read- 

 ing over a broad surface, and the marvelous beauty of the strikingly 

 vivid coloring far surpasses anything of the kind we have seen in this 

 land of wondrous beauty ; every possible shade of color, from the 

 vivid scarlet to a bright rose, and every shade of yellow to delicate 

 cream, mingled with vivid green from minute vegetation. Some of the 

 channels were lined with a very fine, delicate yellow, silky material, 

 which vibrates at every movement of the waters. Mr. Thomas Moran, 

 the distinguished artist, obtained studies of these beautiful springs 

 and from his well-known reputation as a colorist, we look for a 

 painting that will convey some conception to the mind of the exqui- 

 site variety of colors around this spring. There was one most beau- 

 tiful funnel-shaped spring, 20 feet in diameter at the top, bat taperiag 



Fig. 46. 



GREAT SPRING, FIR E-H OLE RIVER. 



down, lined inside and outside with the most delicate decorations. Indeed, 

 to one looking down into its clear depths, it seemed like a fairy x)alace. The 

 same jelly-like substance or pulp to which I have before alluded, covers 

 a large area with the various shades of light-red and green. The sur- 

 face yields to the tread like a cushion. It is about two inches in thick- 

 ness, and although seldom so tenacious as to hold together, yet it 

 may be taken up in quite large masses, and when it becomes dry 

 it is blown about by the wind like fragments of variegated lichens. 

 At the upper end of the lower district are three immense boiling 

 springs on the east margin of the river, and on the opposite side are 

 two or three more, and then comes a long interval of two or three 

 miles which is entirely free from springs, until we reach the upper 

 basin. The immediate valley is covered with old siliceous deposits up 

 to the base of the hills on either side, showing that, although there are 

 no springs at this time, it was once the scene of great activity. The bot- 

 tom over which the river flows is paved with the old silica. The forest 

 grows close down to the margin of the river, and in one place the hills 

 of trachyte almost close in the valley. Iligh up on either side are walls 



