The Maryland House of Delegates on Saturday evening voted to pass a measure that would decriminalize possession of small amounts of marijuana.

The House voted 78-55 to pass an amended version of Senate Bill 364. The bill would decriminalize possession of less than 10 grams of pot by making it a civil offense, punishable by a fine.

The House's vote is significant because lawmakers in the Senate have already passed a similar bill. The Senate is expected to agree with the House's measure and send it to Gov. Martin O'Malley. But any hiccup in the Senate could be costly, as Monday is the final day of the General Assembly's 90-day session.

Earlier in the day, the House Judiciary Committee returned the bill to its original form as a bill that would decriminalize pot. The Judiciary Committee earlier in the week had made a move many thought killed the bill, amending it entirely so that it would only authorize a study of decriminalization.

But a compromise reached between the Judiciary Committee's leaders and supporters of marijuana decriminalization resurrected the measure.

It's unclear if Gov. Martin O'Malley will sign the bill if it makes it to the governor's desk. A spokeswoman for O'Malley said Friday evening that the governor would "review" the bill when and if it passes.

"Should the bill pass, the governor will review and make a decision then about signing," said Nina Smith, a spokeswoman for the governor.

In its current stature, the bill would decriminalize possession of less than 10 grams of marijuana by making it a civil offense, punishable by a fine.

Before law was changed in 2012, the penalty for possession of any amount of marijuana was imprisonment for up to one year and a fine of up to $1,000. The state then reduced the maximum penalty for possession of less than 10 grams to a 90-day jail sentence and a $500 fine. In any case, possession was a criminal offense.

Under the revised bill, the fine for possession of less than 10 grams would be up to $100 for a first violation, up to $250 for a second violation and up to $500 for a third or subsequent violation.

The bill would also require those younger than 21 cited for possession of 10 grams or less to appear in court for their first offense. A judge could refer them for an assessment for substance abuse, which could require them to attend a drug treatment and education program approved by the state Department of Health and Mental Hygiene.

The bill originally imposed a similar requirement for first offenders younger than 18.

The measure specifies that the reduced penalty for pot possession "may not be construed to affect the laws relating to" operating a vehicle or a vessel while under the influence, or law enforcement agencies' authority to seize vehicles involved in violations.

Delegates participated in a passionate debate that lasted past 6 p.m. on Saturday and opposition came from Republicans and Democrats.

Del. Keiffer Mitchell, D-Baltimore, who played a key role in putting together the deal with House Judiciary leaders to revive the bill, said the bill would address racial disparities when it comes to marijuana possession arrests.

The Legislative Black Caucus has referred often during the marijuana debate to studies that show blacks are arrested more often that whites for marijuana possession.

Decriminalization efforts have been promoted across the nation as an expansion of civil liberties and as a civil rights issue.

A 2013 report by the American Civil Liberties Union found African-Americans are 2.9 times more likely than whites to be arrested for marijuana possession. In Anne Arundel County, the study found African-Americans were 2.4 times more likely than whites to be arrested.

In 2010, the study found Maryland spent $106.7 million enforcing marijuana possession laws.

But opponents of the measure said the bill was moving too fast.

"This has been put together on the fly like it's some sort of last ditch effort to save the world," said Del. Michael McDermott, R-Wicomico, a former police chief.

Monday is the last day of the General Assembly's 90-day session. Senate Bill 364 must pass the Senate in the same form before midnight on Monday to go to O'Malley.

Lawmakers will not meet Sunday.