Clearing the way for possible discovery of billions of dollars worth of oil and natural gas, the Supreme Court yesterday let stand a decision to permit the first offshore exploratory drilling off New York, New Jersey and Delaware.

The action was among the most important taken by the justices in their first public sitting since they recessed Jan. 24.

Acting on a far-ranging list of approximately 450 cases, the court disposed of litigation as diverse as taxation and freedom of religion. The justices:

Let stand a ruling requiring public universities -- but only in certain states -- to open campus meeting places to organizations seeking to promote "dialogue" about homosexuality. (Story, Page A9.)

Agreed to decide whether anti-fraud provisions in the federal securities laws apply to certain pension plans. (Story, Pagbe A8.)

Agreed to decide whether countervailing duties must be imposed on Japanese color television sets that Japan exempted from a certain tax. (Story, Page D8.)

In the offshore drilling case, the 2nd U.S. Circuit Court of Appeals held that the secretary of the interior had prepared an adequate environmental impact statement and that exploration in the so-called Baltimore Canyon consequently could proceed.

The adequacy of the impact statement had been challenged -- successfully in a trial court in Brooklyn -- by Suffolk County, N.Y., and environmental groups.

Interior accepted bids of more than $1 billion in August for lease of 93 tracts occupying more than 500,000 acres. More sales are now expected.

Frank Ikard, president of the American Petroleum Institute, emphasized in a statement that "no one knows how much oil and natural gas may be found."

In addition, he said, there will be "a considerable time lag from the start of drilling operations until the country sees its first drop of oil or cubic foot of natural gas."

Delaware Gov. Pierre S. du Pont IV said of the court action, "That's super."

In briefs filed with the court, objectors contended that the circuit court ruling created "a major risk" of pollution in the Atlantic fishing grounds and on beaches.

The National Ocean Industries Association, composed of drilling companies and other firms with stakes in offshore exploration, argued that the delay caused by the trial court "resulted in losses running to several million dollars per week . . ."

The court took other actions;

It agreed to hear a challenge to the constitutionality of a New Jersey law that makes a death sentence mandatory for a person convicted of murder, while a defendant who pleads no contest can get 30 years.

It affirmed, 7 to 2, a ruling that prisoners are entitled to procedural safeguards when a state moves them to a maximum-security facility of Nebraska to review a decision invalidating a state law that allows transfer of a prisoner from a maximum-security facility to a mental hospital without notice or opportunity for a hearing.

It denied a petition by the state of Texas to review a decision that it violated a prisoner's rights when it transferred him from medium-to maximum-security confinement as punishment, he claimed, for having criticized the penal system in testimony before the legislature.

It held out a hope to California of possible large tax collections from the estate of Howard R. Hughes by agreeing to hear arguments -- "in due course" -- on the state's claim that the eccentric billionaire legally was a Californian, not a Texan.

It agreed to hear a challenge to an Illinois law barring payment of aid for dependent children to foster parents related to the children.

It declined a petition by Delta Airlines for review of a decision denying government indemnification for any damages the company paid as a result of a 1973 Boston crash in which 89 persons died. Delta argued that part of the blame for the crash belonged to a federal airtraffic controller.

It declined to review the convictions of two persons involved with a sham abortion clinic in Knoxville, Tenn., in which "abortions" were performed on women incorrectly diagnosed as pregnant.

It agreed to decide whether Massachusetts denied due process of law when, without first affording a hearing, it suspended for 90 days the license of a driver who was arrested for being drunk at the wheel and who refused to take a chemical or breath-analysis test.

It let stand a California Supreme Court ruling under which a prisoner whose legs were crushed while he was a volunteer firefighter was awarded $35 per week for life in unemployment insurance benefits, although he was within a few months of release and almost paid "his debt to society". Had he been a civilian volunteer firefighter when he became a paraplegic, he would be collecting $119 a week for life.

It let stand a ruling that a South Carolina man was guilty of "contributory negligence" and therefore could not collect damages, although he had been seriously and permanently injured being a "good samaritan."

The injury occurred when someone brought a bucket of gasoline into a work site to clean some metal bearings, and put it down next to tanks of oxygen and acetylene. A spark from a welding torch fell into the gasoline and set it aflame.

The man grabbed a stick, put it under the handle, ran, stumbled, and was saved by burning gasoline.