Take a Laurel school teacher who has been RIFed and an Adelphi court reporter on a leave of absence. Add a little experience as a bicycle mechanic, volunteer work with an environmental group and a strong interest in endangered animals. What results is a 4,800-mile journey along the eastern seaboard for the benefit of vanishing breeds such as the short-nosed sturgeon and gopher tortoise.

Since May 1, school teacher Bill Nelson and court reporter Patricia Miller, riding on a bicycle built for two, have been wending their way to Washington from Key West, Fla. By July 1, they hope to reach the Maine-Canada border in an effort to generate public interest in the Endangered Species Act, a measure that is endangered itself unless Congress this summer votes to extend it.

During their journey to Washington, Miller and Nelson said they were surprised to find that although many people knew about the Endangered Species Act, they didn't know the act was due to expire Sept. 30. Miller and Nelson urged people they met along the way to write their congressmen in support of the act's extension.

Nelson came up with the idea of the bike-a-thon when he remembered meeting a man who hiked the Appalachian Trail to raise money for the blind. Nelson said he chose to travel the eastern seaboard in order to meet as many people as possible.

When Nelson and Miller, who have been dating for a year, arrived in Washington, they visited Rep. Steny Hoyer (D-Md.) at the Capitol. Hoyer and Rep. Edwin Forsythe (R-N.J.), a leader in the fight to renew the act, congratulated the bike riders for their effort.

"Being on a tandem bicycle made us highly visible on the highways," Nelson, 27, said. "We were always having people wave us off to the side of the road, take our picture and give us a Coke."

The only problems the sun-bleached pair said they encountered during their sojourn were flat tires and trying to shade themselves from the torrid Florida sun. They also said it took them a long time to get used to riding marathon distances. "We got pretty saddle sore there for awhile and it's still bothering us," Nelson said.

They managed to ride nearly 1,500 miles in four weeks, however--averaging about 54 miles a day--through rainy mountains, swamplands and scorching stretches of southern roadways. "There were days that we made 100 miles, and some that we made only 40 miles," Miller, 25, said.

In Florida, the pair saw a variety of endangered species, including a manatee (a mammal resembling a walrus), alligators and gopher tortoises roaming free in a national wildlife preserve at Cape Canaveral.

"To have seen all of these animals," said Nelson, "well, we just think we were very fortunate."

After their Washington stop, Miller and Nelson reloaded the small yellow trailer they tow, covered with an "Endangered Species Bike-a-thon" tarp, packed up their sleeping bags, a tent, tools, a stove and a few days supply of food. Then they remounted their saddles and set their course for the Chesapeake Bay, the Delaware Bay, New York City, Boston, Cape Cod, Maine's weatherbeaten coastline and Canada--1,310 miles away.

When they return, Miller will go back to her job as a court reporter and Nelson to a new job as a science teacher at Sidwell Friends School. By then, they hope, the Endangered Species Act will be well on its way toward renewal.