At its south end, the Sanctuary takes in a small piece of the Carden Alvar, and the steep limestone slope created by the rough caress of the glaciers. At the foot of this slope, the Head River meanders across the reserve, its spring floods nourishing a rich floodplain forest. Beyond that is a band of mixed forest of oak, pine and birch on pockets of drier soils. But the northern half of the Sanctuary, north of Monck Road, is classic granite barrens with scattered trees and a mosaic of beaver ponds and wetlands. All on this one property, the ecological transition known as The Land Between is fully on display.