316 The Great Canons of the Colorado River. 



The volcanic rocks were pictures of beauty in arrange- 

 ment and in colouring. 



" Probably nowhere in the world/' writes Dr. Newberry, 

 f "is there a finer display of rocks of volcanic origin than may 

 be seen about the southern entrance to the Black Canon. 

 The beetling crags which form its massive portals are composed 

 of dark-brown porphyry of hardest and most resistant character. 

 Just within the canon, on the west side of the river, this por- 

 phyry is mingled with masses of huge, light-brown trachyte; 

 tufa, pure white, or white veined with crimson ; and pale blue 

 obsidian (pearlstone) ; amygdaloids of various kinds, their 

 cavities filled with different zeolites; black and grey basalts, 

 sometimes columnar; scoria, red, orange, green, or black, and 

 of every grade of texture; porphyries in great variety, in- 

 cluding some of unequalled beauty ; trachytes and tufas of all 

 colours ; obsidian in its various forms ; all these are abundantly 

 exposed in the immediate vicinity. 



" The view from the western slopes of. the Black Mountains, 

 which we obtained from the summits bordering the canon, is 

 scarcely equalled in its savage grandeur by any 1 have elsewhere 

 seen. A thousand subordinate pinnacles spring from the 

 mountain side, all displaying the ragged outlines which the 

 materials composing them are so prone to assume, while their 

 colours are as striking and varied as their forms. Not a par- 

 ticle of vegetation is visible in the landscape. As the eye of the 

 traveller sweeps over this wilderness of sunburnt summits,, 

 which stand so stark and still, glittering in the burning sun- 

 light, and yet so desolate, he shrinks from the unearthly scene 

 with a feeling of depression which must be felt to be imagined.''' 



Many excellent records of exploratory work have been 

 issued by the American Government during the last fifteen 

 years, but the memoir of the Colorado Expedition is the most 

 complete of them all, both in text and illustrative plates, maps 

 and sections. 



The certainty that very few English readers will sec the 

 original work, and the extraordinary character of the country 

 traversed, will, it is hoped, justify the lengthened extracts that 

 have been made. 



