"Abstractions in Nature"

The Prince William Art Society presents a group exhibition by local artists. 6 a.m.-10 p.m. Monday-Saturday, Saturday through Sept. 25. Northern Virginia Community College, fourth-floor gallery, 15200 Neabsco Mills Rd., Woodbridge. Free. www.pwcweb.com/artsociety.

Outdoor Concert

The Quantico Marine Corps Band will perform patriotic marches and other popular favorites at 6:30 p.m. Saturday on the lawn of the Manassas Museum, 9101 Prince William St., Manassas. Free. 703-330-2782.

"Falling for Fall"

Watercolor paintings of rural autumn landscapes by Marcia Weidler will be on display. 11 a.m.-4 p.m. Tuesday-Friday, 11 a.m.-5 pm. Saturday and noon-5 p.m. Sunday, Tuesday through Oct. 3. Loft Gallery, 313 Mill St., Occoquan. Free. 703-490-1117 or www.loftgallery.org.

"Layers and Edges"

Artist's Undertaking Gallery will feature mixed-media collages by Alice Webb and turned-wood pieces by Patrick O'Brien. Webb's works, based on her photographs, are three-dimensional and whimsical. O'Brien, using a variety of woods, reveals the layers of each in such pieces as bowls, ring stands and Scottish spurtles, which are kitchen stirring implements. 11 a.m.-5 p.m. daily, Tuesday through Oct. 4. 309 Mill St., Occoquan. Free. 703-494-0584.