THE PROPOSAL ADVANCED by a Treasury Department task force is to phase out the dollar bill over the next year or so and replace it with the Susan B. Anthony dollar coin and the $2 bill. That's like taking Spectacular Bid out of the Jockey Club Gold Cup this weekend and replacing him with Frolicking Miss and Ed Upp -- they both finished out of the money at Timonium this week.

Like them, the Anthony coin and the $2 bill are also-rans. They've been out on the track long enough for the public to demonstrate its clear lack of enthusiasm for both of them. The coin has a fundamental flaw -- it is easily confused with a quarter, which may, actually, be appropriate, since it has only about as much buying power as did the old 25 cent piece. As for the $2 bill, why bother to replace two pieces of paper with one when hardly anyone counts by twos?

If the government is really serious about getting rid of the dollar bill, the people at the Treasury and the Mint need to go back to their drawing boards. To be acceptable, a dollar coin has to be of a size or shape or weight not to be easily confused with some other coin. The old silver dollar, which is worth several times that much now for its silver content, worked fine until modern-day pockets and purses became too flimsy to handle its weight.

The Anthony dollar might have worked if its designers had had the courage of their convictions and made it an 11-sided coin instead of an 11- sided design inside a circle. Or it might work with a hole punched in its middle. The only trouble with the latter proposal is that the coin would then be a constant reminder of what inflation is doing to the dollar's value.

Notwithstanding objections on Capitol Hill, the arguments for phasing out the dollar bill are substantial. The Treasury says that persuading the public to use coins instead would save about $58 million a year in paper. Besides, there is something forlorn about fishing out a bill to pay for a gallon of gas or a hamburger. Those are things that ought to be bought with coins.