{p. 38}

Drift,[1] and also with a peculiar drift-clay (_argile plastique
bigarrée_), plastic and streaked.

Professor Hartt gives a cut from which I copy the following
representation of drift-clay and pebbles overlying a gneiss hillock
of the Serra do Mar, Brazil:

###

DRIFT-DEPOSITS IN THE TROPICS.

_a_, drift-clay; _f f_, angular fragments of quartz; _c_.
sheet of pebbles; _d d_, gneiss in situ; _g g_, quartz and
granite veins traversing the gneiss.

But here is the dilemma to which the glacialists are reduced: If an
ice-sheet a mile in thickness, or even one hundred feet in thickness,
was necessary to produce the Drift, and if it covered the equatorial
regions of Brazil, then there is no reason why the same climatic
conditions should not have produced the same results in Africa and
Asia; and the result would be that the entire globe, from pole to
pole, must have rolled for days, years, or centuries, wrapped in a
continuous easing, mantle, or shroud of ice, under which all
vegetable and animal life must have utterly perished.

[1. "Geology of Brazil," p. 488.]