UPPER MADISON AVENUE
KURT SCHWITTERSChalette, 1100 Madison Ave. at 82nd St. Schwitters dabbled in Dada before embracing an equally nutty style that he labeled Merz. This retrospective of his Merz-drenched collages suggests that yesterday's Dada is today's Pop. Through Nov. 30.
REX CLAWSONRoyal-Athena II, 1066 Madison Ave. at 80th St. Clawson mixes nerve with verve in wax-oil-and-casein commentaries on politics, crime, Mom and libido. Not a fig leaf in the show. Through Nov. 9.
AINSLIE BURKEKraushaar, 1055 Madison Ave. at 80th St. Eighteen tranquil landscapesNew England's surf, dunes, marshes and headlandsthat are well-mannered but far...