GEOLOGIC TIME. 659 



Dr. Woodward says, on the opposite view, that in the earliest 

 geological periods each bed of sand, clay, limestone, etc., had 

 actually to be formed, and that later deposits had the older sedi- 

 mentary ones to furnish material, and, therefore, the newer 

 deposits were laid down more rapidly. 1 This does not impress 

 me strongly ; but from my experience among the Paleozoic rocks 

 I agree with Sir A. Geikie, that "We can see no proof whatever, 

 nor ever any evidence which suggests that on the whole the rate 

 of waste and sedimentation was more rapid during Mesozoic and 

 Paleozoic time than it is to-day. 2 



Professor Huxley, in his presidential address to the Geologi- 

 cal Society of London in 1870, treats of the distribution of 

 animals and says of his hypothesis that it " requires no supposi- 

 tion that the rate of change in organic life has been either greater 

 or less in ancient times than it is now ; nor any assumption, 

 either physical or biological, which has not its justification in 

 analogous phenomena of existing nature." 3 



In the Grand Canon of the Colorado, Arizona, there are 

 11,950 feet of strata of Algonkian age extending unconformably 

 beneath the Cambrian. There is nothing in this section to indi- 

 cate that the conditions of deposition were unlike those of the 

 strata of Paleozoic and Mesozoic time. The sandstones, shales, 

 and limestones are identical in appearance and characteristics 

 with those of the latter epoch. The deposition of sulphate 

 of lime and gypsum occurred abundantly in the upper portions 

 of the series, and salt is collected by the Indians from the depos- 

 its formed by the saline waters issuing from the sandstone 8,000 

 feet below the summit of the series. The sandstone and shales 

 were deposited in thin, even laminae and layers, and the sun cracks 

 and ripple marks give evidence of slow, uniform deposition. In 

 the upper part of Chuar terrane there are 235 feet of limestone. 

 And in one of the layers of limestone, 2,700 feet below the sum- 

 mit of the Chuar terrane, I find abundant evidence of the pres- 



I Geol. England and Wales, 2nd Ed., 1887, p. 23. 



2 Rept. Sixty-second Meeting Brit. Assoc. Adv. Sci., 1892, p. 19. 



3 Quart. Jour. Geol. Soc, Vol. 26, 1870, p. lxiii. 



