108 THE LAPSE OF TIME. 



present surface. These layers contained distinctive relics. 

 In the first were found * Roman tiles and a coin,' in the 

 second { fragments of unvarnished pottery, and a pair of 

 tweezers in bronze ;' in the third, ' fragments of rude 

 pottery, pieces of charcoal, broken bones, and a human 

 skeleton having a small, round, and very thick skull.' 

 The thick-headed owner of that skull is computed to 

 have lived, at the lowest estimate, about five thousand 

 years ago. But the cone of the delta began to be 

 formed long before the man was buried in it, and higher 

 up the stream another cone is found about twelve times 

 as large, requiring therefore a time for its formation 

 about twelve times as long, unless we have recourse 

 to that miserable refuge for the destitute in argument, 

 which consists in supposing that causes now slow and 

 comparatively regular, operated in former times with 

 an incomparably greater speed and a more spasmodic 

 violence, of which no trace remains, nor likelihood 

 appears in the record. In a word, we may infer that, 

 so far from the shapely order and decorous arrangement 

 of the earth's surface being only six thousand years old, 

 it has taken no less than fifty or a hundred thousand 

 years to pile up this one little heap of mud and gravel. 

 The age of human works buried under the fertilizing 

 sediment of the stately Nile is much disputed, but there 

 can be little doubt, if we take into consideration the 

 ancient fluviatile deposits in terraces sometimes hundreds 

 of feet above the present alluvial plain, that the long- 

 unknown sources of the mysterious river have pro- 

 duced ten myriad repetitions of the annual overflow, 



