At the horizon the land mass becomes a continuous pale neutral grey.地平线上的大片土地变成了绵延的浅灰色。The new territory would extend over one-fifth of Canada's land mass.这块新领土面积可达加拿大大陆面积的五分之一。Dinosaurs evolved when most continents were joined in a single land mass.恐龙进化的时候，多数大陆连为一体。