Logic suggests that Pleasant Colony is a virtual certainty to win the Belmont Stakes the the Triple Crown Saturday. Only history suggests otherwise.

In the last quarter of a centry, 11 horses have come to Belmont Park after capturing the Kentucky Derby and the Preakness. Only three -- all great champions -- have succeeded here. The list of failures includes many horses who looked just as formidable as Pleasant Colony.

There is no mysterious jinx responsible for the shattering of so many dreams here. The Belmont is a difficult, demanding race for several very specific reasons.

Some horses lack the inherent ability to win at its 1 1/2-mile distance. Even a great horse like Northern Dancer, who could run brilliantly at 1 1/4 miles, was incapable of negotiating the extra two furlongs. He didn't have the genes.

More often,horses lose the Belmont because the rigors of the Triple Crown campaign have already taken a physical toll on them. Majestic Prince was on his last legs when he came here in 1969. Canonero II was ailing in 1971.

Sometimes, the Triple Crown horses are ambushed by a fresh new shooter in the Belmont. Stage Door Johnny peaked just at the right time to defeat Forward Pass in 1966. Coastal blossomed late and upset Spectacular Bid two years ago.

Are any of these factors relevant to Pleasant Colony?

Although the floppy-eared colt with the skin blemish won't win any equine beauty contests, he is sound and robust. He is one of the rare 3-year-olds whose health hasn't even been the subject of rumors. "This is just about the first good horse I've ever had who doesn't have any problems," said trainer John Campo.

There is no way to peer into Pleasant Colony's genetic makeup and know whether he can go the Belmont distance. But he looked like a strong horse at the end of the Derby and the Preakness, and his pedigree will certainly not stop him at 1 1/2 miles. His sire, His Majesty, had classic breeding, and one of his other offspring captured a stake at 1 3/4 miles this spring.

Pleasant Colony seems unlikely to be ambushed by any new, fresh challengers on Saturday. There are no Stage Door Johnnys or Coastals in the field for the 113th Belmont. The favorite has already trounced most of the horses who are considered contenders.

Oddly, the horses who finished closest to Pleasant Colony in the Derby and the Preakness do not appear formidable challengers at all. Bold Ego lost by a length at Pimlico after taking an easy early lead and setting a slow pace, but if he could not beat Pleasant Colony that day, he never will. His trainer, Jack Van Berg, conceded, "I'm really not sure he can get the the 1 1/2 miles," and said today that he might scratch his colt Saturday morning.

Woodchopper certainly looked like a potential mile-and-a-half horse when he finished strongly to be second at Churchill Downs, but that was something of an optical illusion. Because the early leaders were collapsing after a suicidal early battle, many horses finished fast in the Derby. Most of them did nothing in their subsequent starts. Still, trainer Jack Gaver feels genuinely optimistic. "I expect a big race out of him Saturday afternoon," he said.

Pleasant Colony's principal opposition may come two colts he defeated soundly when they were running under less-than-ideal circumstances.

Tap Shoes finished 14th at Churchill Downs, but he missed a crucial prep race before the Derby and was coming into it after a five-week layoff.

He has prepared for the Belmont in optimal fashion, winning the Peter Pan Stakes in respectable time and then working a mile in a swift 1:37 this week. He will probably be the second choice in the wagering Saturday.

Highland Blade bypassed the Derby, came into the Preakness after a disadvantageous four-week layoff and lost by 11 lengths. But trainer David Whiteley was probably aiming for the Belmont all along, and he is such a cautious horseman that he wouldn't enter this race on a lark. Highland Blade's breeding and running style suggests that he may be a natural 1 1/2-mile horse.

The others shooting for a share of the $284,300 Belmont purse are Bare Knuckles, Escambia Bay, Summing, Stage Door Key, Paristo and Sezyou.

If any of them beats Pleasant Colony, handicappers are going to have to add a whole new category to explain upsets in the Belmont Stakes.