America's new urban working class was drawn primarily from what two groups?

Social class in the United States is a controversial issue, having many competing definitions, models, and even disagreements over its very existence.[1] Many Americans believe in a simple three-class model that includes the "rich", the "middle class", and the "poor". More complex models that have been proposed describe as many as a dozen class levels; [2][3] while still others deny the very existence, in the European sense, of "social class" in American society.[4] Most definitions of class structure group people according to wealth, income, education, type of occupation, and membership in a specific subculture or social network.

Sociologists Dennis Gilbert, William Thompson, Joseph Hickey, and James Henslin have proposed class systems with six distinct social classes. These class models feature an upper or capitalist class consisting of the rich and powerful, an upper middle class consisting of highly educated and affluent professionals, a middle class consisting of college-educated individuals employed in white-collar industries, a lower middle class composed of semi-professionals with typically some college education, a working class constituted by clerical and blue collar workers whose work is highly routinized, and a lower class divided between the working poor and the unemployed underclass.