The Type 1 dollar features three islands off the coast of Florida - All of them are east of the eastern edge of the Gulf of Mexico (or western edge of Florida). The varieties of this year largely deal with the styling of the depiction of earth on the reverse of the coin and the differences are very subtle - but easy to distinguish.
One major variety is the 1972 Type 3 Eisenhower 'Ike' Dollar - also known as Variety 3. What This Coin Looks Like (Obverse, Reverse, Mint Mark Location, Special Features, etc.):
