Underground Rivers - University of New Mexico

Chapter 7 -- The Concept of Circulation
And lest anyone should imagine... that ... swallets in general might have been formed by river
water, let it be remembered that they are commonly found upon the tops of the highest
mountains, especially such as have extensive flats, where neither river nor rain-water could
have any force to tear such Cavities, and therefore they could not owe their origin to such a
Cause.
[Fissures connecting with the Abyss] serve as canals for the Water which supplies Springs and
Rivers to run in.
Alexander's brother Georgeheld a similar opinion.
In the Roof of these Caverns, and upper Parts of the Sides, are a great Number of Cavities in
the solid Rock, in Form of inverted Funnels, which as they widen in Proportion to their Depth,
prove they could not have been made by Art [i.e. mining}, (as some have absurdly asserted)
but by the Retreat of the Waters which flow thro' them, into the great Abyss beneath, at the
Time of the universal Deluge.-- A Descriptive Account of a Descent Made into Penpark-Hole
(1772, 1775).
By the 18th century, however, fewer and fewer scholars saw reason piece together God's doings
in that week of creation. The task at hand was that of finding a model that explained modern
nature.
There was need to reconcile three perceptions regarding rivers.
The circle as an unbroken expression of God's holiness,
An Aristotelian impressions that streamflow exceeds rainfall, and
The Platonic belief in subterranean reservoirs and channels.
The Dual Hydrologic Cycle
As put by Ramazzini, "The arms for the springs are two arms," the hypothesis of the dual
hydrologic cycle.
Evaporation
Ocean
Precipitation
Rivers
Underground
Rivers
The Dual Hydrologic Cycle
Clouds
Land
Caverns
Springs
The upper loop, that which can be observed upon or above the earth's surface, agrees with
modern pluvial theory, though today we'd include factors such as a box representing vegetation.
The lower loop, that which is within the earth, disagrees with modern evidence, but we not hold it
against those working in an era before evidence was considered. We'll bring the diagram up to
date in Chapter 38, Hydrogeology.
A dual cycle made sense in a time when water was thought to have opposing effects: water from
above eroding of the continents and water from below rejuvenating the mountaintop.
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