be the result of the constant pushing and butting by the plates as they try to go their separate ways. The San Andreas Fault in California is perhaps the most famous of the boundary zones between the twenty-odd plates currently recognized; it forms the boundary between the North American Plate and the Pacific Plate. Thus, San Francisco's situation at the edge of a plate accounts for its frequent violent earthquakes while Connecticut's position in the middle of a plate (but the edge of a continent) makes for a somewhat more stable future.

Plates do not take kindly to getting shoved around. When two plates converge, enormous pressures build up that compress, crack, and fold their edges. As a result, mountain ranges are pushed up. The parcels of rock that get caught in this wrestling match are the terranes. Millions of years after the fracas subsides, the history of the convergence can be read from terranes - they are snapshots of the past.

Because the Earth has a finite surface area, all this shoving of plates is like people in a crowded elevator: when one person or plate moves, the rest have to shift slightly to accommodate the change. An important implication is that plate movements are truly enormous events, affecting huge areas. The scenes in Connecticut's geologic history that can be read from terranes are but small episodes in a global geologic drama. Thus, much of what is known about local events in Connecticut is drawn from regional observations that put the happenings here in perspective. Plate tectonic analysis shows that Connecticut's geologic history is related to events recorded in rocks on both sides of the Atlantic Ocean, from Argentina to Greenland, South Africa to Norway, and on the Atlantic Ocean floor as well. The ability of plate tectonics to fit together so many far-flung pieces of the geologic elephant is perhaps the theory's most convincing aspect. Today, plate tectonics is accepted by almost all geologists as the most accurate picture of the elephant, what it eats, how it moves, where it's been, and where it's going.

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