32 



KNOWLEDGE 



[February 1, 1892. 



no trace of movement can be detected, so it has probably 

 ceased. 



With regard to these displacements, there is some very 

 interesting evidence which goes to show that these earth- 

 movements took place slowly — in accordance with the 

 " theory of uniformity " of the action of geological agents, 

 which may be said to be the very basis of modern geology. 



already alluded to, viz., the Hnrricane '• fault." In each 

 case they cut through lava flows, which are evidently 

 pretty recent ; therefore they must be subsequent to the 

 time when the flows took place. Mr. Powell has shown a 

 connection between monoclinal flexures and "faults." They 

 often shade into each other, and it looks as if the bending 

 of the strata went on until a point was reached when the 



Fig. III.— Niches or Panels in tlie Red Wall Limestoue, Gnujd Caiiou Distriet. 



The old theories of sudden catastrophies and revolutions 

 have been superseded by the teachings of Hutton and 

 Lyell. 



One of these displacements, known as the Toroweap 

 " fault," exemplifies this point very clearly ; for excepting 

 the dislocation itself, the " faulting "does not appear to have 

 been accompanied by an injury to the strata. There is no 

 trace of any shattering, crumbling, or smashing of the 

 strata. All looks as clean and sharp as if it had been cut 

 with a thin saw, and the smooth faces pressed neatly 

 together. The plane of the " fault " is nearlv vertical. A 

 careful study of its surroundings shows that "it is of recent ! 

 occurrence. None of the " faults " of this region seem to 

 have been produced in a violent manner, but to have been 

 gradually developed through long stretches of time, inch 

 by mch, or foot by foot. Many facts go to prove the ' 

 modern character of this " fault," as also of the other one 



tension could no longer be borne, and a split was the 

 result. This might aptly be illustrated by the long, sharp, 

 and clean fractures that take place in a sheet of ice after a 

 number of people have been skating on it. At first the ice 

 only bends, but after a time the tension becomes too great 

 and results in fractures. 



It is not necessary to describe in any detail the rocks of 

 the Colorado j^lateau. Suffice it to say that the strata of 

 each and every age are remarkably uniform over very 

 large areas, especially in their lithological characters, and 

 were deposited very nearly horizontally. In thickness 

 and composition they are very persistent. The changes 

 are always gradual. Local deposits, formed in small areas, 

 are absent. They were all formed horizontally. The 

 limestones are in great abundance in the Carboniferous 

 rocks, but in the Mesozoic system limestones are rare. By 

 far the greater part of the series of rocks exhibited in this 



