Montezuma Well is a
separate part of the monument, located 11 miles northeast, near Rimrock,
Arizona. The Well is a natural
sinkhole through which some 1,400,000 gallons of water flow each day.
The water is highly carbonated and contains high levels of
arsenic. At least five
endemic species live only in the Well: a
water scorpion, an
amphipod, and a
leech -- the most endemic species in any spring in the Southwest US.
- From Wikipedia, the free