The General Assembly today finished its business for the year with unaccustomed tranquility, enacting the remaining major pieces of legislation before it with few of the last-minute debates and entanglements that usually characterize adjournment night.

Well before the midnight deadline, two bills that were the centerpiece of the leadership's package on state prisons had been enacted, along with the final priority of the legislative leadershp and Gov. Harry Hughes -- a new program for disposal of hazardous wastes.

Still, in the last half-hour, as is always the case, the 188 delegates and senators raced about, trying to wrap up matters of somewhat less significance.

At 11:30 p.m., it appeared that a measure designed to punish underage drinkers by suspending their drivers' licenses would die when a conference committee failed to agree on the wording of the measure. Finally, after the committee held a third meeting, the House agreed to Senate amendments that would allow a judge to decide whether a youth's drinking offense warranted suspension of the coveted license. After a few frantic minutes in the clerk's office searching for the proper bill and rushing it to the speaker's desk, the measure passed with only two minutes to spare.

Another touch of drama was added to the midnight adjornment when Sen. Edward J. Mason (R-Cumerland) filibustered the state's $45 million school construction loan program. As Mason was talking with only seven minutes to go, House Speaker Benjamin L. Cardin appraised the dire situation, interrupted business in his chamber and rammed through another version of the school loan bill. The clock was striking midnight just as Cardin was explaining to his House colleagues the slick maneuvering he had just accomplished.

The ultimate resolution of these matters was in keeping with a three-month session during which the leadership was able to move dozens of major bills and hundreds of lesser ones through both houses with unusual alacrity.

Indeed, by the time the House broke for lunch today, Cardin and Majority Leader Donald B. Robertson (D-Montgomery) found that the most important issue they had left to discuss was whether messages to thanks and congratulations would be adopted by resolution, or simply included in Cardin's closing remarks.

"This is a dream come true for the last day," said Cardin shortly after noon. "I have a very relaxing day ahead of me. "We're spending lots of time doing things that don't have to be done.

"Then, after another moment of thought, Cardin added: "There's not a thing left on the leadership's agenda that has not been accomplished. It's almost frightening."

The corrections measures enacted by the legislature today, which were the subject of a compromise between Hughes and legislative conservatives six weeks ago, provide for the construction of a 500-bed prison and seven community-based rehabilitation centers.

The two bills --along with another mandating a second new 500-bed prison -- appeare to settle a long-standing dispute inthe legislature over how many prisoners the state should provide space for and where new maximum security institutions should be built.

The hazardous waste legislation would give the state rather than local officials final control over the selection of sites for disposal of hazardous wastes in the state, allowing the state to set up a broad program for controlling toxic waste disposal.

In other actions in the final hours, the assembly:

All but killed off the nation's only remaining statewide movie censor board, which will go out of existence next year if the 1981 General Assembly fails to revive it. The state's sunset law required the legislature to take positive action to keep the board, but the House, which championed it, and the Senate, which voted to gut the board, were unable to agree on legislation. Last-minute meetings today failed to produce a compromise.

Enacted the final bill in a package of measures that will raise the cost of consumer loans and virtually everything a consumer buys on credit.

Killed a perennial measure that would have required truckers to cover loose loads of material with canvas as a safety measure.

Enacted a measure requiring gasoline stations to post their prices, legislation aimed at encouraging price competition among dealers.

Provided state bonds for the restoration of two historic mansions in Prince George's County -- the Montpelier House and Magruder House.Bond money for a third such house in the county, the Buck House, was rejected due to a last-minute filibuster by Del. Robin Ficker (R-Montgomery).

The day's lackluster final votes were in keeping with a session that was usually calm and free of confrontation.

The legislative initiative that drew the most national publicity during the session was Republican Sen. Howard A. Denis' abortive attempt to do away with the state song, "Maryland, My Maryland," because its lyrics betrayed distinct Confederate sympathies. A tradition-minded Senate committee killed that bill.

Overall, however, it was the welcome influx of unexpected revenues that set the tone for the legisltive season. From New Year's Day on into March, estimates of new revenues plus unspent funds from last year rose from $229 million to $320 million.

As the extra money kept coming in, discord turned to harmony on one issue after another.

First, Hughes added $17 million to his education aid proposal, fulfilling the wishes of lawmakers from the state's poorer jurisdictions.

Legislative leaders quickly decided to turn this something-for-everyone measure into an insurance policy to guarantee passage of a potentially more controversial pair of bills: those providing $90 million in aid for the state's mass transit and road networks.

These measures, proposed by Hughes after two weeks of intensive debate and formula-juggling by the governor's staff, were built around a proposed $5 to $8 increase in the annual vehicle registration fee. While this was less objectionalbe than a gasoline tax increase as far as lawmakers were concerned, it still represented a form of tax increase -- something politically unpalatable in a year of excess revenues.

Then, within six weeks, a new set of revenues estimates came to the rescue. With the totals now peaking at $340 million, Hughes abandoned the registration fee increase. Instead, he decided to contribute an extra 1 percent of the state's corporate income tax to transit needs.

With this extra $20 million, it was possible to meet all the goals of the package -- including providing $23.2 million for the Washington area Metro system next year -- without finding a new revenue source.

But as the surplus continued to rise, so did the level of legislative discontent with state spending policies. While few legislators offered objections to spending programs that helped their districts, many turned to advocacy of proposals setting a ceiling on state budget increases.

These antispending sentiments reached their apex in late March, when a bare majority of the House Appropriations Committee's members staged a mini-rebellion, approving a package of six measures to curb government growth.

The measures, which among other things tied the annula increase in state spending to the comparable increase in the earnings of the state's taxpayers, were moving easily through the Senate at the time.

This 11 to 10 vote in the House committee, a direct affront to the wishes of Hughes, Cardin and most of the legislative leadership, prompted a counterattack in both legislative chambers. Hughes and his aides went to work in the Senate, calling droves of lawmakers up to the governor's office to hear arguments against bills that would, Hughes said, remove the necessary flexibility from the budget-making process.

This, the most notable lobbying effort of Hughes' 15 months in office, was matched on the House side, where Cardin and his lieutenants spend a day telling one local delegation after another that the spending limits package would mean an end to much of the state money that flows to individual counties.

A few days later, the bulk of these measures were killed in the House and Senate.

While that lobbying effort matched most others in intensity, it was in no way comparable with the session-long efforts of the black caucus to win enactment of the constitutional amendment giving the District of Columbia congressional representation.

Early session visits by D.C. Del. Walter Fauntroy, who came to push the bill, were marred by a set-to with two Jewish legislators who demanded that Fauntroy criticize the Palestine Liberation Organization. Unless he did so, they said, they would withhold their support of the voting rights amendment.

Since the bill failed by one vote in 1979, the potential defection of these two delegates seemed crucial. But, in the end, the members of the legislative black caucus traded enough votes withother blocs to delegates to make with other blocs of delegates to make up for the defections. The amendment won 71 House votes, exactly the number needed for enactment.

"There's nothing left in the store" to trade, commented Prince George's County Del. Nathaniel Emum just before the final vote.

The perennially sensitive issue of state funding for poor women's abortions was also resolved through negotiation, although once again it took a conference committee of senators and delegates to arrive at a compromise.

This group agreed to a slight modification in the existing requirements that poor women must meet to qualify for state-funded abortions. Now a doctor must certify in writing that an abortion is needed to protect a woman's health.

In addition, if a doctor decides a pregnancy is dangerous to a woman's mental health -- the reason cited for 82 percent of Medicaid abortions in Maryland -- he must specify that the operation is necessary to protect the mother's current and future mental health.

Many measures of interest to the state's consumers and environmentalists, including a package of bulls promoting energy conservation with tax incentives and a bill requiring a 10-cent deposit on beverage containers, died well before the session's end. So did most of the tax relief measures proposed, including one increasing the standard deduction for state income taxpayers.

The most arcane tax relief measure to win approval was one exempting the "manure banks" used by the state's farmers from the state property tax.

A tax proposal affecting a somewhat different interest group -- the members of Montgomery County's country clubs -- failed when the measure, which put a tax on country club memberships, was killed by the county's Senate delegation.

Among the other proposals that died this year were measures providing an automatic cost-of-living escalator for those receiving state unemployment insurance and two measures affecting fund-raising for statewide candidates.

For the fifth straight year, a measure providing public funding for candidates for statewide office was killed -- only this year it was abandoned by some of its most consistant supporters. Over the weekend, a bill limiting campaign contributions by major state contractors was also defeated.

And the emotional early session drive to raise the state's minimum drinking age for wine and beer to 19 foundered after the introduction of an alternative measure, providing automtic suspension of drivers' licenses for juveniles who violate state drinking laws.

There was no stopping another pair of bills aimed primarily at Maryland's younger citizens. Within the last week, the assembly enacted two laws banning the sale, possession and use of a variety of articles used to consume marijuana, hashish, cocaine, heroin and other drugs.

g the constitutionality of these measures is still in question, as similar laws in other states have been challenged in the federal courts.

The unusually calm and orderly progress of legislative business this year was exemplified by the handling of the state budget bill -- a measure providing 11 percent increases for welfare recipients and 7 percent hikes in state employes' pay. The $5.2 billion budget was approved two weeks ago, well before the statutory deadline.