^{page 276 note 1} This appears to be the rationale of M. Tresca's experiments, by which he proved that solid, ductile, or pulverulent bodies, can, without changing their states, flow in a manner analogous to that of liquids, when sufficiently great pressure is exerted on their surface.

^{page 279 note 1} If we understand the present Director of the Canadian Survey, he no longer regards the Grenville series as Laurentian, that designation being restricted to the gneiss without limestone, which alone represents the fundamental series.