The Grand Etang Forest Reserve, encompassing elevations from 300 metres at St. Cyr to 760 metres at an unnamed peak in the Reserve’s north, displays a combination of ridges, the upper headwaters of over 10 steep-sided coastal valleys and the upper basin of a major tributary of the Great River. The Reserve contains four of Grenada’s highest mountains: Southeast Mountain (712m), Mount Sinai (700m), Mount Qua Qua (713m) as well as the unnamed peak (760m). All of volcanic origin in the Pliocene and Pleistocene Periods, these mountains dominate the physical landscape. Volcanic activity also contributed to the formation of Grand Etang Lake as a crater lake: one of three explosive craters in the Reserve. Slopes on the flanks of these mountains and connecting ridges are generally in excess of 20 degrees and often in excess of 30 degrees. Grand Etang Lake empties into the tributary of the Great River.