TRACKSIDE GEOLOGY

Experienced gardeners have learned you must look hard at natural landscapes before you try to recreate them on your layout. They learn to see the various kinds and colors of rock, where the strata and grain lie, how the soil erodes around them, and how climatic changes weather rock faces or cause them to break. They also notice how plants grow around exposed rock. Two books you may find helpful: Bill McClanahan's Scenery for Model Railroads (Kalmbach Publishing), especially the chapter entitled "Short Course in Railroad Geology", and the Roadside Geology series from Mountain Press Publishing. Geology may be fascinating. Road cuts show how to imitate sedimentary rock strata. Hill tops are really broken ridge lines and if you look at several hills you may imagine the line once connecting them. Major ridge lines are very evident in aerial views. Developing them is a good way to enhance the realism of your layout. Valleys between hills expose the bare rock bones of a ridge and ridges are always in line with the way the rock formed eons ago. When you dig a canyon, remember it is most typical to use the same kind of rock on each side, with the same weathering, and to display strata lines in the same direction. On the other hand, canyons eroding at the fault line where two different kinds of rock meet may require more modeling skill and careful attention to real scenery. In Sonoma County, California, where we live, rocks seem to be a jumbled , folded, sheered mess and some outcroppings look as though somebody stirred them with a stick.

PICKING ROCKS

A good place to look for rock, as you might guess, is a landscape rock yard or a building materials supplier and most will deliver for a small charge. Picking your own rocks in the country should be a last resort because of the time it takes and the necessity of asking a property owner's permission. If you plan to build stone retaining walls, culverts, or tunnel portals you might also consider manufactured stone products. When you start to landscape, choose long, narrow, sedimentary rocks so the strata appear natural when you stack them one above the other. Use jagged igneous rock rather than rounded river stone. Igneous rocks do better in odd-numbered groups. When the edges prevent them from fitting together, plant them as in a boulder strewn field with soil separating the individual rocks. In some cases you may even want to create rocky areas artificially using chicken wire and mortar as indoor modelers do, but be careful. Nothing looks worse than obviously artificial scenery.

PLANTING TECHNIQUES

Put in the rocks before you put in the plants. It will help you visualize realistic scenes. Most layouts lend themselves to one major ridge line and it often looks best somewhat parallel to the length of the area. If you actually stake out the ridge line it will give you a better point of reference for putting in the rocks and moving a lot of earth. Fashioning mountains seems easier if you first build up the soil, then dig holes in it for the rocks. And don't forget drainage, following both the natural runoff of your yard and what you create with your landscape and roadbed. Remember rocks and boulders, with few exceptions, appear to grow out of the earth. You may create the illusion of greater depth by planting progressively smaller rocks as you work up the ridge slope. And tilt the rocks backwards as you plant them so water drains toward the back, not the front. The idea is to avoid washes and landslides; they'll erode the soil around your vegetation and bury your track, just as on full-scale railroads. Scatter smaller stones and rubble along the base of larger rocks to represent erosion. When you are satisfied with the overall contour of your work, sprinkle everything thoroughly to settle the soil. Make any adjustments the rocks may need and water again.

AND NEXT TIME...

You now have the basic outline of your landscape but it may look a little barren. In the next issue we'll bring color, texture, and life to your layout by adding miniature trees.