6. Less than one million years ago the glaciers advanced over the park area. The glacial ice plucked and scratched (striated) the underlying rocks as it slowly advanced southward. During the retreat (northward) certain deposits were left. Present-day Burke Mountain is much the same as it was when the glaciers left, but, some added erosion has taken place and, because of uplift, the Mountain stands a bit higher than it did some 10,000 years ago. Some soil, much of which was removed by the glaciers, has since formed on the mountain. There are no rocks present in the park which were deposited during this interval of time, therefore, no rock record. If no rocks representing this time interval are present, one of two reasons must be responsible. Either the park area was undergoing active erosion (wearing down) during this period, or sediments were deposited during part or all of this time interval and subsequently completely removed by erosion. Most probably, the intervening time found the park area above the depositional environment of the sea, when its rocks were being worn away by the erosional forces of nature. Again, see Figure 17 for a diagrammatic representation of the geologic history of the park. WHY IS THERE A BURKE MOUNTAIN? Granite is a very resistant rock, that is, it wears away very slowly under the forces of nature. The granite is worn down more slowly than the metamorphic rocks which it has intruded. The granite has been squeezed between and across the layers (bands) of the metamorphic rocks (previously sedimentary rocks) now found on Burke Mountain. In a very true sense, the granite forms a skeleton framework for the metamorphic rocks of Burke Mountain. In other words, it holds these metamorphic rocks up above the surrounding area of metamorphic rocks. HIKES TO TAKE A very interesting hike, both geologically and for nature hunting in general, is the old fire road which begins just above the old C.C.C. camp and the present Bell Gardens. This trail cuts off to the right, if ascending the summit road, and runs completely around the mountain. Shortly after the fire trail intersects the Bear Den Ski Trail, and on the left, granite with obvious drill holes is seen (Fig. 18). Most of the granite used as curb stones, culvert headers, and islands along the park summit road was obtained from these small quarries. A few miles walk along this trail proves quite rewarding to the adventurer; an old lean-to demonstrates what a bear can do while sharpening his claws. The Devil’s Den Trail leads down the east side of Burke Mountain from the observation tower at the summit. This trail is rather poorly marked past a certain point, but if you wish to strike off on your own and see some wonderful country, a hike down this trail with a swing to the north will bring you back to the summit road.