This is the true truth
about that stupendous undertaking, which is to create a new
Mediterranean in the midst of the Dark Continent, and to modify the
climate of Northern Europe to something like the condition of the
Glacial Epoch. A new Dead Sea would be much nearer the mark, and the
only way Northern Europe would feel the change, if it felt it at all,
would be in a slight fall in the price of dates in the wholesale market.
No, Sahara as a whole is _not_ below sea-level; it is _not_ the dry bed
of a recent ocean; and it is _not_ as flat as the proverbial pancake all
over. Part of it, indeed, is very mountainous, and all of it is more or
less varied in level. The Upper Sahara consists of a rocky plateau,
rising at times into considerable peaks; the Lower, to which it
descends by a steep slope, is 'a vast depression of clay and sand,' but
still for the most part standing high above sea-level. No portion of the
Upper Sahara is less than 1,300 feet high--a good deal higher than
Dartmoor or Derbyshire. Most of the Lower reaches from two to three
hundred feet--quite as elevated as Essex or Leicester. The few spots
below sea-level consist of the beds of ancient lakes, now much shrunk by
evaporation, owing to the present rainless condition of the country; the
soil around these is deep in gypsum, and the water itself is
considerably salter than the sea. That, however, is always the case with
fresh-water lakes in their last dotage, as American geologists have amply
proved in the case of the Great Salt Lake of Utah.
Pages:
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429