Contributed by Jonathan Agin / Formed by erosion over millions of years, Chaco Canyon was the site of the Ancestral Puebloan people’s sprawling urban center. Buildings erected there in the eleventh century were among the tallest in North America until the nineteenth. These remote, enigmatic ruins, marked on early Spanish maps, were rediscovered in the modern era by US Army surveyors after the Mexican-American War. Today they are part of the Navajo Nation, which covers parts of Arizona, New Mexico, and Utah. When Anne Wehrley Björk was a child, her family used to take her camping there. As demonstrated in “Lost Canyon,” her new show of paintings at Margot Samel, she has never forgotten the landscape.