Federal Reserve chair Janet Yellen, delving into unusual territory for the nation’s central bank, Friday described how “concerned” she is by widening income inequality and questioned whether current trends are incompatible with fundamental national values.

Yellen said by many measures, the gap between the richest Americans and average households has reached to the worst levels since the 19th century.

“The past few decades of widening inequality can be summed up as significant income and wealth gains for those at the very top and stagnant living standards for the majority. I think it is appropriate to ask whether this trend is compatible with values rooted in our nation's history, among them the high value Americans have traditionally placed on equality of opportunity."

Also unusual for a Fed chair, Yellen called out the wide discrepancy in school funding between rich communities and poor, citing better education as one of the major steps to, over time, reduce income inequality. Yellen noted that the U.S. is one of the few countries that funds primary and secondary education by local or state taxes, not national.

While the Fed’s ability to address income inequality is limited – its power and focus are around interest rates and inflation – Yellen’s remarks were widely greeted as unusual and important in the income debate – all the more so given that her predecessor, Ben S. Bernanke, steered clear of the question. In a 2007 speech, for example, Bernanke said he would “not draw any firm conclusions about the extent to which policy should attempt to offset inequality in economic outcomes, because that determination inherently depends on values and social trade-offs and is thus properly left to the political process."