called traprock, a volcanic rock. The mountain formed near the end of the Triassic Period with the rifting apart of the North American continent from Africa and Eurasia. Lava welled up from the rift and solidified into sheets of strata hundreds of feet thick. Subsequent faulting and earthquake activity tilted the strata, creating the dramatic cliffs and ridges of Mount Norwottuck. Hot, dry upper slopes, cool, moist ravines, and mineral-rich ledges of basalt talus produce a combination of microclimate ecosystems on the mountain that support plant and animal species uncommon in greater Massachusetts. References The Metacomet-Monadnock Trail Guide. 9th Edition. The Appalachian Mountain Club. Amherst, Massachusetts, 1999. Farnsworth, Elizabeth J. "Metacomet-Mattabesett Trail Natural Resource Assessment." 2004. PDF file. Cited Nov. 20, 2007. "Amherst College Library Chronology". Cited from web Dec. 2, 2007. The Metacomet-Monadnock Trail Guide. 9th Edition. The Appalachian Mountain Club. Amherst, Massachusetts, 1999. Mt. Holyoke Range Historical Timeline. Cited from web Dec. 2, 2007. Raymo, Chet and Raymo, Maureen E. Written in Stone: A Geologic History of the Northeastern United States. Globe Pequot, Chester, Connecticut, 1989. Mt. Holyoke Range Historical Timeline External links J.A. Skinner State Park Map Mt Holyoke Range State Park Map Hampshire College mountain biking map of the Holyoke Range Berkshire Chapter of the Appalachian Mountain Club The Kestrel Trust Natural resource assessment of the Metacomet Ridge Geology of the northern Metacomet Ridge region State website for Skinner State Park Mountains of Hampshire County, Massachusetts Holyoke Range Mountains of Massachusetts