Hauling heavy wheat loads down steep grades using teams of horses or steers with the brakes applied the entire descent was long and dangerous. Even today the roads used to access the canyon are steep and low gear and brakes need to be applied even in a light passenger car. An approach to avoid the steep dangerous grades was building grain slides. These involved wooden tubes that funneled the wheat to the river below. The initial design worked, but the heat generated toasted the wheat black. With baffles and vents the system worked better. Coordination was required however with loading the slides at the top and bagging the wheat below. A tram system was built in the Mayfield area. Bill Gulick included a fictional description uses of the tram system in his historic novel Roll on Columbia and reports that at least five grain slides were operated along the river.
While making a drive down to the canyon bottom in the eastern Palouse, I noted a road called Tramway Road that skirted along the upper edge of the canyon and decided it would be worth the minor added distance on the route to the canyon bottom. The route led to great views of the canyon and had the added surprise of the remnants of an old tramway used for hauling wheat to the river.
Top of old tramway with river below
Trace of tramway route down the slope. The canyon is 1,600 feet deep.
The lower Snake River is still heavily used for grain transport. In fact with the lower four dams river transport can be done with large boats and over a longer period of time. Trucks and development of paved roads has eased access to the river and with bulk transport the old wheat slides and tramways have been long out of use.
I should add a brief note on the geology of the canyon. The horizontal bands on the slopes are primarily various basalt lava flows of the Columbia River basalt group. However, the base of the canyon at this location has eroded down into the underlying ancient continental margin.