The lithosphere's most striking characteristic is that it is divided into two main levels. The lowlands, filled by water form the oceanic basins, and the highlands which we call continents, rise some two and a half miles above the much lower oceanic basins. This division of the surface into highlands and lowlands is shared with both Mars and Venus. 

Continental topography 

On average, continents rise some two and a half miles above the ocean floors (one half mile above sea level). Generally, continents have mountains along their margins (#4) and a rather stable, lower interior called the craton or shield (#5). Usually they are bordered by coastal plains (#3) and occasionally there are internal mountain ranges separating major cratonic areas. 

Seaward of the coastal plains, margins of continents are relatively flat and shallow ranging from sea level to 600 feet in depth. The width of this continental shelf (#2) varies from a fraction of a mile to hundreds of miles. At the seaward edge of this continental shelf, there is an abrupt increase in slope (shelf break between #1&#2), and the steeper continental slope (#1) drops towards the oceanic depths. At the base of the continental slope there is one of two features. Some continents are bordered by a wedge of materials derived from the continent, less steep and angled more gently than the slope, the continental rise (#6). Other continental edges lack the continental rise and, instead have deep trenches (#10) along their margins. 

Ocean floor topography 

Hidden from view by a cover of water averaging over two miles in depth, the rocky ocean floor reaches nearly 36,000 feet in its deepest parts. Far from being an old, flat and featureless abyss as was envisioned in the last century, the topography of the ocean floor is as, if not more, varied as that of the continents. A generalized cross section reveals the following features as we continue to move toward the middle of the ocean. Beyond the rise or the trench, we encounter abyssal plains (7), relatively flat, featureless expanses of ocean floor. Slowly rising from these plains, a continuous globe-girdling mountain range, over 40,000 miles long, the mid-ocean ridge (#8), extends into every ocean basin of the world. 

The central axis of this ridge is commonly marked by a crack, the mid-ocean rift (#12), which splits the ridge into two nearly symmetrical halves. Occasionally, the ridge is interrupted along its course by tremendous offsetting breaks (fractures) that run at right angles to these ridges called transform faults or fracture zones. In places, islands rise from this ridge. 

Other features are also commonly found on, or rising from the ocean floor. In places there are enormous outpourings of lava that have created what we call Large Igneous Provinces or oceanic plateaus. There are many arc-shaped island chains  stretching for hundreds or thousands of miles. There are two types of oceanic islands. Some are associated with trenches in the ocean floor (#11), others are not (#13). Often these island chains continue below sea level as flat-topped seamounts (guyots).