542 THE POPULAR SCIENCE MONTHLY. 



in tlie species, even without the aid of the physical changes 

 which then took place, than are apparent in the species now exist- 

 ing. There is, in fact, no sufficient evidence either geological or 

 biological to show the need of the long interval assumed. On the 

 contrary, there is every reason to believe that it did not exist, but 

 that palaeolithic man and his companions came down to within 

 some ten to twelve thousand years of our times. We can not 

 suppose that either man or geological work would have remained 

 stationary during seventy thousand years, and yet that is the 

 conclusion we should be driven to adopt. Are we to be debarred 

 from pursuing these inquiries by a hypothesis having no better 

 foundation, and involving such unquestionable difficulties ? 



Another barrier to inquiry is the postulate which would fix 

 the rate of upheaval of the land during geological periods upon 

 observations based not upon the experience of even two or three 

 thousand years but upon observations which do not extend be- 

 yond two centuries. These observations have shown, as put by 

 uniformitarians, that the mean rate of elevation of the coasts of 

 Norway and Sweden has been during that time two and a half 

 feet in a century, and this scale has been accepted and employed 

 unhesitatingly as a safe and sure basis for calculation of geologi- 

 cal time. The determination of a secular rise of the land is of 

 itself an interesting fact, as settling the question of a retained 

 mobility in the earth's crust ; but it is quite insufficient, even if 

 it were applicable, to establish a definite rate, not only for the past 

 but even for the present. It is not a mean rate that is wanted. 

 No upheaval can be otherwise than local and graduated. The ex- 

 tremes are what is needful. No engineer would take the mean 

 delivery of a river as the measure to be depended upon for a 

 water supply. It is the limit in both directions, or the minimum 

 and maximum quantities, that are essential. To know what earth 

 movements can still effect, we should at least take the maximum 

 rate, which amounts in the above case, at the North Cape, to five 

 feet in the century, or double the measure of the mean adopted 

 by uniformitarians. 



If also, in calculating the present rate of elevation of the land, 

 the mean rate along the whole length of the axis is adopted, the 

 same rule should at least be applied to elevations of past periods, 

 and the time should not be estimated by the height of any one 

 point, as that may prove to be more or less in excess of the mean. 

 Thus, for example, the Westleton marine shingle is found in 

 Buckinghamshire at a height of six hundred feet. Estimating this 

 ujjheaval at the rate of two and a half feet in a century, the 

 uniformitarian would put in a claim for twenty-four thousand 

 years. But this bed, as it trends eastward, is met with at grad- 

 ually lower levels, until in Suffolk it falls to the sea level. A 



