"Chronologists are agreed that about 2000 years B.C. Abraham migrated from Mesopotamia to Canaan, and that at this time Egypt at least was old in civilization. Beyond this we have no positive scale of time in Scripture; for it is evident, from the narrative itself, that the latter does not cover the whole time. * * * "Ussher estimates from Scripture the creation of man as about 2000 years before this. During the latter portion of this time civilization was proceeding under settled governments in the East, interrupted, says the record and tradition, by a flood. * * * "So Lucretius: 'Thus, too, the insurgent waters once o'erpowered, As fables tell, and deluged many a state; Till, in its turn, the congregated waves By cause more potent conquered, heaven restrain'd Its ceaseless torrents, and the flood decreased.' Barbarism covered the whole Western world; neither in the 2000 years before Abraham, nor in the 2000 years afterward, have we any light reflected from these regions to the East. In this 4000 years, or in the somewhat longer period which probably will be ultimately settled as warranted by the record, we place hypothetically all the phenomena of the later mammalian age, including the introduction of man as a hunter, the first occupation of the caves by him also, the diluvial phenomena of the wide valleys, the oscillations and disturbances of the earth's crust, alterations in the coast-line, and physical settlement of the country; after this comes the second occupation of the caves. In short, if we say that, hypothetically, the whole first known human age occurred within 4000 years of the Christian era, no one can say that it is geologically impossible. Who can say that 1643 years is insufficient to comprise all the phenomena that occurred during a period confessedly characterized by more rapid and extensive action than at present--a period during which ruptures in the earth's crust, oscillations, and permanent uprising took place, and the intermittent action of violent floods caused the deposit and disturbance and resettlement of the gravels and brick-earth? There is nothing to interfere with the prevalent opinion that man was introduced here while the glacial period was dying out, and while it was still furnishing flood-waters sufficient to scour and re-sort the gravels of the valleys down which they flowed. This supposition may be extended to both the great continents."