y, the westering waves of migrant English met other waves of
Scotch-Irish and the Germans coming down from Pennsylvania, and before
the American Revolution the combined breeds of men had built up enough
pressure to push Indians almost entirely out of the Potomac Basin and to
occupy all the good farmland, even in the Basin's ridged western areas.

Since then their successors have used the land for farming and for other
purposes. In using it they have changed it, and the changes have
registered in the river system that drains it. For land, water,
vegetation, wildlife, minerals, and men's habits are not separable from
one another in the natural frame. So that if the early planters, using
methods of hoe tillage scarcely less primitive than those of the
Indians, mined the Tidewater soils for tobacco production in a way that
required new fields every few years, one result was that those soils
tired and thinned and finally stopped supporting the social magnificence
that had grown up there, for production and prosperity moved inland and
west. And another result was that the Potomac estuary itself grew
shallower and different with the silt that washed down off the land, and
many a tributary bay that once served as harbor for oceangoing ships is
now a rich, reedy marsh with a single narrow gut of shoal water
wandering down across it to the Potomac.

And if later generations of men cut down the forests on the mountains in
the western Basin, and fire followed the cutting, thousands of years of
soil washed down from those slopes too to change both mountains and
river, and elk and panther vanished. And if along the Potomac's North
Branch there was once a fine coal boom, there is now the boom's legacy
in the form of gray dour towns and dark sad streams corrosive with mine
acids.

And if old Alexandria and Georgetown and all the land around them have
burgeoned into one of the nation's great cities, there has been a price
to pay for that also. The stately upper estuary on which they front is
often turbid with silt and sometimes emerald green with algae nourished
on sewage and other septic riches, and the hills stretching back from
the river are spiky with tall buildings linked by urban and suburban
clutter, where life lacks the natural elbow room that the old Tidewater
folk--planters and yeomen and bondsmen and slaves alike--were able to
take for granted.

These are facets of an Age of Problems, of course. They and other
related tro