The first and last thirds of the route were entirely over mountains. The middle third traversed the irrigated basin around Grand Coulee Dam. No matter how many times Richard flew it, he was always startled to see the ground suddenly level out and develop a rectilinear grid of section-line roads, just like in the Midwest. Early on, the pattern was imposed in fragments scattered over creviced and disjoint mesas separating mountain valleys, but presently these flowed together to form a coherent grid that held together until it lapped up against some terrain that was simply too rugged and wild to be subjected to such treatment. The only respect in which these green farm-squares differed from the ones in the Midwest was that here, many of them sported inscribed circles of green, the marks of center-pivot irrigation systems.