The study deals essentially with the morphogenesis of the constructed environment in downtown Shawinigan, for the period 1900-1930. The initial elements of the research, concerning « unicellular forms » and morphological groupings, are presented in table form. The demonstration relies primarily on the distinction between the logic of the « merchant form » and the theory of the urban form, which both contribute to the understanding of the urban phenomenon. Thus we find a company, on the one hand taking advantage of a national resource — hydroelectricity — and closely associating itself with big industry in order to exploit the labour force and, on the other hand appropriating a portion of space that it intends to put to use... by creating a town.