Stories in Stone: How Geology Influenced Connecticut History and Culture

5. The Metacomet Ridge: The Scientific, Political, and Cultural Impact of an Old Lava Flow

The Metacomet Ridge The Scientific, Political, and Cultural Impact of an Old Lava Flow Before the time when Connecticut acquired a reputation as “the land of steady habits,” —in the days, perhaps, of its wild oats, so to speak, it was the field of volcanic activity of far greater power than has ever been manifested by Vesuvius. —William Pynchon, 1896 Anyone familiar with the devastation in Pompeii and Herculaneum caused by the 79 ce eruption of that mighty volcano will find Pynchon’s statement to be a stretch. After all, there is no sign of a volcano in Connecticut, not even the deeply eroded remains of one. However , Pynchon was right: volcanism destroyed much more territory here than the infamous Vesuvius ever did in Italy. Connecticut’s volcanic remains occur in a long, narrow ridge that rises as much as five hundred feet above the adjacent lowlands and dominates the topography of the Central Valley. The ridge was named after Metacomet, also known as Pometacom or King Phillip (fig. 5–1), a sachem of the Wampanoag peoples who played an important role in an especially violent native uprising against the settlers. Legend has it that he and his followers spent time in a cave in the northwestern corner of Talcott Mountain, a segment of the ridge, from which they could control part of the Farmington valley. c 5 1. Assuming the floors of a building to be ten feet high, the flow’s maximum thickness is equal to that of a sixty-story skyscraper, a little more than half the height of the Empire State Building. The ridge is exposed inside a rift valley and stretches almost unbroken from Amherst to Meriden. In the Meriden area, however, a swarm of north-northeast-trending faults offsets the hills to the east. Because of significant vertical motion along these faults, the ridge broke into segments, or fault blocks, each with its own name: South Mountain, Cat Hole Mountain, Lamentation Mountain, and Chauncey Peak. From Mount Beseck in Middlefield, the Metacomet Ridge can be traced farther south to East Haven (plate 2, bottom and fig. 5–2). The Metacomet Ridge is the erosional remnant of a 500- to 600foot -thick lava flow, a slab of rock that filled the entire Central Valley around 200 million years ago.1 The flow, named after the town of Holyoke , tilted to the east tens of millions of years later, together with the entire contents of the rift zone. As a result, the ridge became asymmetric in profile and now exhibits precipitous western and gently dipping 106 stories in stone Fig. 5–1. Metacom (Pometacom) or King Philip, after whom the basaltic backbone of the Central Valley was named. The different “portraits” show the stereotypical views about Connecticut natives commonly held by its residents in the early (left) and late (right) halves of the 19th century. Fig. 5–2. Connecticut rift valley showing the location of exposed lava flows/sills (thick lines). The Holyoke flow was predated by the Talcott and followed by the Hampden basalt. Note location of New Haven and Hartford on different sides of the Metacomet ridge. Thin lines in the Highlands represent possible feeder dikes. eastern slopes. Segments of the flow west of the ridge eroded and became part of the sediments deposited offshore, while younger sandstone formations bury the flow east of the ridge. Massive sheets of ice that scoured Connecticut in the more recent geologic past greatly accelerated the erosion of the Metacomet Ridge. Steep northeast- and northwest-trending clefts developed where ancient faults cut the lava sheet. They broadened into gorges when the ice pushed through and removed the broken-up basalt. The lower slopes of the steep western flanks of the ridge are typically coated with talus, large aprons of loose basalt blocks that grow each winter when the process of ice wedging detaches rocks from the cliff face. The ridge remained undeveloped for centuries and presently forms a scenic green belt in the densely populated Central Valley, a seemingly untouched wilderness that separates urban and suburban agglomerations on either side. Although obviously quite different topographically, this strip of land could be referred to as Connecticut’s Central Park. John Whittier, a well-known poet, greatly admired the ridge and wrote the following verse in 1838, after visiting Daniel Wadsworth’s property, “Monte Video,” on the crest of Talcott Mountain, west of Hartford...