Conglomerate cliffs are made up of many pebbles and smooth stones that became cemented together over a long period of time. Since it is difficult to sculpt something that looks authentic, the exhibits team decided to make a cast of an actual cliff in the Cypress Hills.

The forested Cypress Hills, the only area in the province not covered by glaciers during the last ice age, seem out of place in the flat expanse of the southwestern prairies. The exhibit technicians spent the first day hiking around the cliffs to find a nice example of conglomerate formation that was within a reasonable distance from their truck and supplies.

They began making a mold by painting a thick layer of liquid latex rubber on the rock face, and brushing on strips of cheesecloth to give it strength. The next layer was applied after the first was dry, and this process was repeated until the rubber was six layers thick. When the finished mold was pulled away from the cliff, it weighed roughly 50 kilos and was extremely floppy! The crew wrestled the heavy rubber pancake up the hill, struggling to keep their footing on an avalanche of loose pebbles.

Now they had a perfect "negative" of the cliff face. Back in the exhibits workshop, a wooden form was built to hold the mold in a cliff-like shape. The rubber was then sprayed with a greasy mold-releaser, which made the cast easier to remove when it was finished. Next, a thin layer of polyester resin gelcoat was applied to form a smooth outer surface for the cast. Behind that, the bulk of the cast was added; a special expanding foam that becomes very tough when it hardens. To give added strength, a wooden skeleton was embedded in the foam.

It took five people to wrench the mold from the cast, but after all the hard work, out came a perfect replica of the conglomerate cliff. Now, the only thing missing was colour. To reproduce the subtle variety of colours they saw in Cypress Hills, each faux pebble and rock was painted by hand with latex washes. The result? A very authentic-looking cliff from the Cypress Hills!