Crust (geology) Mars comprise secondary crust, as do the lunar maria. On Earth, we see secondary crust forming primarily at mid-ocean spreading centers, where the adiabatic rise of mantle causes partial melting. Tertiary crust is more chemically-modified than either primary or secondary. It can form in several ways: The only known example of tertiary crust is the continental crust of the Earth. It is unknown whether other terrestrial planets can be said to have tertiary crust, though the evidence so far suggests that they do not. This is likely because plate tectonics is needed to create tertiary crust, and Earth is the
The Public and its Problems the public and its potential. Dewey did not call for an abandonment of the public; rather, he hoped the public would regain a sense of self. The solution to this, he writes, is improved communication. Only then, with communication, will the public find itself and become a cohesive group. In addition to Dewey's proposition that the public cannot find itself because there are too many publics, he also blames the distractions of modern society. He points out that even in the past, the public has had other concerns than politics: "Political concerns have, of course, always had strong rivals". In