The "Iron Quaker Brick Machine" was one of several types of horse- powered machines employed at Connecticut clay pits around the turn of the century. Horses hitched to a bar attached to the top pivot of the Iron Quaker drove the bricks molds.

than 1,200 men. The operations had a capacity of over 300,000,000 bricks each year - enough to build a wall eight bricks high along the entire perimeter of Connecticut." Output today is considerably reduced, but four pits are still active in the Central Valley. Many of the abandoned pits have filled with water to form small ponds, while others have been used as landfills and filled with garbage.

More glamorous than brownstone, crushed traprock, sand a and gravel, and clay (though much less profitable) are the many small copper deposits of the Central Valley. Enough of these mineral masses are scattered about that the Central Valley was sometimes called the "Cop- per Valley". These minor accumulations of copper were deposited when hot, mineral-laden juices associated with flows of traprock permeated the underlying brownstone. None of the copper deposits is large enough to support mining on a modern scale, but many small mines were opened in the 1700s and 1800s. One of these mines became the infamous Newgate Prison Mine in East Granby, Connecticut, where captured Tories were jailed underground in the mine tunnels during the Revolutionary War. Following the Revolution, Newgate was used as a high-security prison for Connecticut's worst criminals, who were kept hard at work, plying the rock walls with hand tools. Finally, the prison was shut down in 1827 after many escapes (some of the inmates did a little extra tunneling on their own), several riots, and much public outcry concerning conditions in the mine. Although recent research has shown that conditions probably were not quite as bad as propaganda of the day made them out to be, the mine was never used as a prison again. A few private individuals tried to work the deposit following the close of the prison, but none proved economically successful. Many of the prison buildings have survived, and the mine is currently preserved as a state historical park.

Perhaps the most unusual mineral deposit in the Central Valley is the Cheshire barite veins. Barite, a heavy white mineral composed of barium and sulphate, is used in paint, pottery glazes, and as an additive to the special fluids needed to drill for deep oil wells. It was also once put to a more questionable use. During the 1800s, powdered barite was sometimes used to adulterate flour. Its white color allowed a merchant to

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