There being no native Washingtonians to speak of, we need reminders that the city and region have always been more than the seat and setting of the national government.

"Washington on the Potomac" at the Corcoran uses our ancient river as a thread on which to string a wildly miscellaneous and thoroughly enjoyable assemblage of prints, paintings, photographs and pottery.

It's a tenuous theme that just suffices to carry the show. One comes away with a general impression, not because the show is coherent but because the works are mainly minor and unmemorable; scarcely half can be described as "art" of any sort.

Which is not to say the exhibition is a grab-bag, since each work evokes history if not aesthetics. Many evoke both, such as "The Great Blizzard of 1899," a watercolor by Walter Paris (1842-1906) that captures the nautical quality of a raging snowstorm.

"Panorama of the Seat of War" (1864), a chromolithograph by John Bachmann, while it has somewhat faulty perspective, gives perhaps a better sense of the geography of this region than any other two-dimensional representation ever executed. At a glance it makes clear how Jackson used the Valley of Virginia to such devastating effect, why Lee was so fatally attracted to Antietam and Gettysburg, and why Lincoln went nearly mad with frustration for lack of a general who would press on to Richmond.

"Octagon House," an 1889 watercolor by A.C. Harkness, is slight in itself but likely to refresh one's rage against the greedy vandals of our time who barricaded that magnificent building. "Capitol, Early Morning" by Childe Hassam (1859-1935) arrests the eye by its willful falseness. It requires the viewer to resist, and therefore engage, the work; which is as much as one can ask of art.

Rosalind Solomon's "White House Gate," a silver-print photograph, lies somewhere in that fruitlessly disputed region where photography passes from a craft to an art. Technically it is a whiz-bang, but technique nowhere shows.

The heart and bulk of the show are landscapes, which though generally weak, contribute the most by showing the landforms we have all but obliterated. Together with Linda Simmons' brief but well-considered catalogue text, they constitute a four-dimensional survey of the capital region, the fourth dimension being time. Besides rummaging thoughtfully in its own attic, the Corcoran borrowed works from scores of sources, giving a breadth to the exhibition that would be hard to match.

WASHINGTON ON THE POTOMAC -- At the Corcoran through April 3.