The evidence bearing upon the rheology of the " tectonically<br />significant layers" of the Earth (" tectonosphere ") in the intermediate<br />time range (4 hours to 15000 years) is analyzed. This evidence is<br />based upon observations of rock-behavior in the laboratory, of seismic<br />aftershock sequences, of Earth tides and of the decay of the Chandler wobble.<br />It is shown that of the rheological models (Maxwell-material, Kelvin-material,<br />and logarithmically creeping material) advocated in the literature, only that<br />based on logarithmic creep does not contradict any of the observational<br />evidence available to date. In addition, a strength limit may be present.