demise here, thrust deep below into the Earth's mantle as Proto-North America and Avalonia steadily approached each other.

But why is there anything left of the Iapetos Ocean rocks at all? Why wasn't the whole business consumed by the subduction zone? As the Iapetos Ocean floor was pushed into the subduction zone, the lighter sediments that blanketed the heavy oceanic crust were scraped off and preserved above to become the Iapetos Terrane. It was kind of like someone eating only the bread part of an open-face tunafish salad sandwich. The bread - the oceanic crust -has been consumed, but much of the tunafish salad - the ocean sediments - we see preserved as the rolling Windham Hills and Southwest Hills of the Iapetos Terrane.

In addition to the light ocean sediments that were scraped off as the oceanic crust descended into the subduction zone, Iapetos rock has been preserved in another way. During the early stages of the collision, big slabs of Iapetos sediments were thrust west over Cameron's Line onto Proto-North America. These displaced sections of Iapetos Terrane overlie much of Proto-North America's granitic gneiss and marble, at one time creating much controversy among geologists concerning the meaning of these clearly dislocated rocks. But geologists now agree that the rocks of the Taconic Plateau and certain other western New England mountains actually have been shoved tens of miles west over Proto-North America by the forces of the collision. By these two processes of scraping off and westward thrusting of sediments, the collision transformed the Iapetos Ocean into land. Jedidiah Morse hardly could have chosen a more apt analogy than when he described the rolling Uplands as an ocean of hills.

Although Connecticut's Uplands today are just moderate-sized plateaus and rolling hills, at the culmination of the collision they were lofty mountains. The best picture of what the land looked like at the height of the crunch comes from a comparison to where a continental collision is actively taking place today: the Himalayas. Evidence from the Indian Ocean floor indicates India was at one time a separate continent. But 30 to 40 million years ago it began a collision with Asia that still continues, thrusting skyward the world's highest mountain chain. It seems likely that the closing of the Iapetos Ocean threw up a similar belt of Himalayan-sized mountains along the line of the collision, crumpling

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