Someone once wrote that there is no social mobility in America. To which I say: When something offends your common sense, don't believe it.

I attended grammar school at Incarnation of Our Lord in Olney - always called "Inky" - for eight years and graduated in June 1950, right in the middle of what has been called "America's Century." The performance of my graduating class is a reminder of how the United States changed in the last half of the 20th century.

Incarnation back then occupied about half of a large city block, extending from Fifth Street on the west to Fourth Street in the east. It was bounded on the south by Lindley Avenue and on the north by a row of houses along Duncannon Avenue. Incarnation was solidly built of a grayish-white stone and designed to last in a very Catholic, utilitarian way. It is still operating - more than 85 years after it opened.

The school was run by the Immaculate Heart of Mary order of nuns, whose habit was dark blue and set off with a tight wimple. It was an overwhelmingly clerical and feminine society, managed by incredibly competent and self-assured women.

How the nuns kept us under control is beyond my imagination. Contrary to the sort of parochial school stories depicted in the play Nunsense, it wasn't based purely on fear or physical punishment.

The average class in my time was between 30 and 34 students. Boys and girls were in separate classes, which was a tradition at Incarnation but not at other Catholic grammar schools. Our classes were merged only for special occasions, such as spelling or geography bees.

In a sense, my graduating class was a microcosm of what happened to America in the last half of the 20th century. There were 34 of us. There were no doctors or lawyers among our parents, and only a handful held white-collar jobs. Our parents' jobs were typical of working-class, rowhouse Philadelphia at mid-century: a barber, an accountant, an insurance adjuster, a beer distributor, a few truck drivers, and a number of men who worked in foundries or construction. No one was poor, but neither was anyone rich.

Of my classmates, most would go on to graduate from high school or technical school. Two became university professors with doctorates, one a physician, and two successful lawyers, and three went on to have solid careers as high school teachers.

In other words, just under a third of the class of 1950 would go to college, and another half-dozen would earn advanced degrees of some kind. So much for no mobility in America.

John P. Rossi is a professor emeritus of history at La Salle University and the author of "Tales of Lower Olney: A Memoir of Growing Up in Philadelphia in the Late 1940s and Early 1950s" (Closson Press), from which this was adapted. He can be reached at rossi@lasalle.edu.