On Sunday, September 20, the class of Geog 2020 went on a field trip to observe the biophysical characteristics of the Ottawa area. Our first stop was at Erskine Johnson Elementary School in Kanata, where there is a large visible outcrop of Precambrian rock in the schoolyard. Our next stop was the March Highlands Conservation Forest, a forested area that features beaver ponds and sandstone beds. Next we moved on to the Crozier Pit, a mining play near Renfrew that features a large outcrop of Precambrian marble and a deep pit with layers of sediment visible on an outer ridge. Our last stop was the Fourth Slide of the Bonnechere River, which is the site of the Bonnechere Caves. Before entering the caves, my group studied the fossil-covered rocks along the rapids of the Bonnechere River. And then we had our guided tour of the beautiful limestone caves of Bonnechere. In this article I will explain and elaborate on my observations. In the Erkine Johnson Public Schoolyard there is a large outcrop of Precambrian metamorphic gneiss. This rock has been heavily weathered over millions of years, to the point that no glacial streaks are visible on the rock's surface. The metamorphic foliations within the rock are unweathered and visible. It is a coarse-grained rock, as can be seen in figure 1. Throughout the rock outcrop there are three different generations of ingenious dykes cutting across the surface (see figure 2). There are three different types of dyke forming rocks throughout the exposed gneiss, diorite, apilite and pegmatite. The dark-colored dykes are diorite, a fine-grained rock that weathers more rapidly than gneiss, as observed from the trenches created along the dykes illustrated in Figure 3. Als...... middle of paper ..... .or pressure. The vortices created rooms large enough for multiple people to stand. On the walls of the cave you can see several layers of sedimentary limestone with wavy patterns. Within some layers some fossils can be seen. The roof and walls of the cave slowly leak water. This water carries calcium carbonate particles, when the water drips this calcium carbonate is left behind and slowly as these particles build up creating icicle like features called stalactites. The inside of the cave is not a very suitable habitat for most animals without artificial lights, it is dark and cold, however bats that prefer dark places have settled in the caves. The numbers, however, are no longer what they once were when the caves were first explored by Tom Woodward in 1955 (figure 23). Figure 22: Wet and wavy structure of the walls of the Bonnechere cave..