My thanks to Jonathan Yardley for focusing on the report by Lynne Cheney, chairman of the National Endowment for the Humanities, on the demise of U.S public education {Style, Sept. 7}. My own experience as a member of the Arlington County Citizens' Advisory Committee for Social Studies is consistent with Mrs. Cheney's indictment of professional educators.

Earlier this year, I read James Kilpatrick's op-ed article "Lost in Geography" {Apr. 4} and then did some follow-up work to obtain a copy of the test administered to 5,000 high school seniors in eight major cities. I intended to propose that this test be administered in Arlington during the week of Nov. 15-21 in conjunction with "Geography Awareness Week," the brainchild of Sen. Bill Bradley.

At the May 1987 meeting of the advisory committee, I distributed copies of the test and Mr. Kilpatrick's article and made my recommendation. A heated discussion followed. Those of us who favored administering the test were subtly belittled by the curriculum "specialists" and professional educators with a vested interest in the status quo as small-minded, naive and uninformed about current teaching strategies. The character of their objections was entirely in line with Mrs. Cheney's report. One of the reactions to our proposal was: "What could be gained by administering such a test?"

Perhaps such a test would reveal that students are not being taught the basic facts and knowledge that were commonplace in curricula a generation ago. Such information is as essential today as it was then for a basic understanding of world events.

My proposal was torpedoed by those professional educators who for years have been assuring concerned parents that incorporating geography into world culture courses does not result in a dilution of the subject. "It's just a change in teaching strategy, in keeping with current trends in educational philosophy," we were told. The relatively innocuous resolution to recognize Geography Awareness Week was, however, adopted.

Apparently, professional educators are not interested in substance or content. But as Mrs. Cheney's report reveals, they are preoccupied with "instructional objectives," "learning activities," "teaching strategies" and "evaluative measures." It is this group of people who are driving more and more parents to seek alternative forms of education for their children. Is it coincidental that increasing numbers of children are being educated at home or in private, church-related schools?

I hope Mrs. Cheney is not destined to be a "voice crying in the wilderness," but rather a prophet whose timely counsel will be heeded. LAWRENCE G. CHERNEY Arlington