A 25-year-old New Carrolton man has been indicted by a federal grand jury on charges of stealing U.S. government property-a shark's tooth and a fish fossil.

The tooth, estimated to be 5 million years old, and the fish fossil, a 50-million-year-old Green River Wyoming sting ray, allegedly were taken from the Smithsonian Institution two years ago by Calvin F. Allison Jr., 25, who is accused in the indictment.

Allison, a salesman at the Hechinger hardware and lumber store in Landover, is a fossil enthusiast who worked as a volunteer at the Smith-sonian from 1973 to 1977 preparing fossils for study by scientists.

"The whole thing is a raw deal," Allison said yesterday. "I've been through this with these guys [the U.S. Attorney's office] before. They've been trying to pressure me to tell them the story the way they want it told."

"I've alwasy been really interested in fossils, even when I was a kid," said Allison, who grew up in Hyattsville and graduated from DuVal High School and Prince George's County Community College. "I though about trying to study them in college but they didn't have the courses. So I worked at the Smithsonian instead."

Alison, who if convicted could be sentenced to as much as 10 years in prison and fined up to $10,000, would not discuss thee merits of the case, saying only, "They're trying to make this into something that it's not."

According to the charges, the fossils were missed from the smithsonian's natural history division in the spring of 1977 and were discovered in Allison's possession.

The two fossils that were allegedly stolen are the four inch shark's tooth, worth about $300 according to Allen Graffham of Geological Enterprises, a scientific supply company in Oklahoma, and the fish fossil, worth as much as $10,000, Graffham said.

Smithsonian spokesman Tom Harney confirmed yesterday that Allison had worked there and said the incident marked the first time in memory that someone working inside the institution has been accused of stealing government property. He said the two items in question were not meant for display but for study by Smithsonian scientists. He said the Smithsonian would not comment on the case.

Allison said yesterday he was planning to contact a lawyer. "The whole situation is just ridiculous," he said. "These guys have been trying to play FBI on me. Believe me, this isn't like they show it to you on television. It's really depressing."

A U.S. attorney's office employe said, "Everyone's taking this whole thing very seriously. I mean, it isn't every day that you try to prove that someone walked off away with two things that are millions of years old. This is no joking matter to anyone, especially the Smithsonian."