New Defender's Study Bible Notes
13:10 well watered. In the early centuries after the Flood, a great ice sheet probably covered the northern latitudes, and this in turn led to abundant rainfall in the southern latitudes, a “pluvial age” corresponding to the “glacial age” farther north. There is much evidence of this all over the world, with remains of extensive settlements and agriculture in regions which (like the region where Sodom and Gomorrah once thrived, near the southern end of the Dead Sea) are now oppressively hot, dry and desolate.
13:16 numbered. It would be as impossible now to count Abraham’s descendants as to count the dust of the earth. He was the progenitor of all the Israelites, of course, but also of all the Arab nations, as well as the peoples of many now-extinct nations–Edomites, Midianites, etc.