D.C. detectives arrested eight Georgetown University students and 10 other persons yesterday in a series of predawn raids on campus dormitories and student residences in neighborhoods near the university, and charged them with selling cocaine and LSD.

Among those arrested were a high-average accounting major who plans to study this summer at Oxford University, the son of a foreign service officer, a National Merit Scholar and others from well-to-do families who live on Fifth Avenue in New York, in the exclusive Connecticut suburbs of New York City and in Malaga, Spain.

During the raids on residences off campus, police said, they seized a pound and a half of cocaine, which they said had a street value of thousands of dollars, 30 "hits" (doses) of LSD and a small quantity of marijuana.

The arrests, which came in the last week of classes at the elite Jesuit university, followed a nearly nine-month-long investigation by an undercover detective who infiltrated the student drug scene.

Operating principally from a student pub in the basement of the Gothic and stately main administration building, Healy Hall, the detective made contact with a number of students and others who are now accused of selling him drugs.

According to court records, the detective spent several hundred dollars in police funds on several packets of LSD and various amounts of cocaine.

Police officials said they moved onto the campus as they continued an investigation of cocaine dealing in Georgetown that previously has included arrests of sidewalk vendors and drug dealers operating out of bars in the area.

Georgetown and other affluent upper Northwest neighborhoods are unique in that they have been the scenes of the majority of cocaine arrests in Washington, said Sgt. Patrick Lanigan of the 2nd Police District vice squad. Large quantities of drugs were purchased on upper Connecticut Avenue in the Foxhall Road area and on Prospect Place NW as a result of contacts made during the Georgetown University investigation, Lanigan said.

"I wish it never happened. I just hope the consequences aren't serious," said Georgetown University junior Martin Stephen Tully, 21, after he pleaded innocent in court to the charge of selling LSD.

Tully, who has a scholarship to attend Oxford's Center for Management Studies this summer, was awakened and arrested by police at 4:30 a.m. yesterday in a house at 1401 Foxhall Rd. NW that he shares with other Georgetown students. He said he had returned only an hour earlier from the university library, where he was working on a 30-page term paper on international accounting that is due on Thursday.

Several of the students who appeared before U.S. Magistrate Lawrence S. Margolies at the U.S. Courthouse yesterday appeared visibly shaken as they stood before the bench, lawyers at their side, and politely responded to Margolies' questions.

One student, Phillip Frank Garone, a National Merit scholar in his freshman year was arrested after midnight in his dormitory room and charged with selling cocaine. At the hearing later yesterday, he turned in shock to his lawyer, his eyes bulging, when a bail officer announced that there was no vertification of his parents' Brooklyn address, which could have caused Margolies to order him held in jail. A friend in the courtroom vouched for him and then Garone, through his lawyer, asked Margolies for permission to travel to New York so that he could explain his situation to his parents, face to face.

"Everybody is talking about this today," said one Georgetown student who asked not to be identified. "I wouldn't say there is a sense of panic, but you can believe that drugs are going to go underground now at finals time when people use speed [amphetamines] to stay up to study."

In addition to the Georgetown students, police also arrested two students at George Washington University and another who attends American. Others arrested included a 26-year-old computer analyst, a 35-year-old man who said he works as a stagehand at various Washington theaters. Another man arrested works in the admissions department at Georgetown Hospital. One of the students arrested works as a emergency room technician full time and attends classes at Georgetown.

The eight Georgetown students and five other arrested all pleaded innocent yesterday in the federal and local courts. The U.S. attorney's office dismissed charges against five other persons, three of whom will be subpoenaed to testify before a federal grand jury investigating the case. Law enforcement officials said yesterday that arrest warrants have also been issued for five other persons in connection with the case.