Introduction to the genesis of planetary structure and Terrestrial Maria

A relationship is drawn between the surface features of the moon and the surface features of the earth. The comparison implies crustal expansion and digestion where the crust fractures and thins in ocean basins, the old fractured lighter crust, being part of the ancient continuous crust, forms the continents. The continents are formed of lighter chemical fractions which float on the heavier more basic younger crust. A simple mechanical system is given to explain the processes involved and surface evidence is given to strengthen the argument. The paper is an introduction to a new concept in global geology, — the process of crater tectonics.