DIASTROPHISM AND THE FORMATIVE PROCESSES 521 
action could have arisen from a primitive fluidal condition is the 
task of those who postulate that state. 
Under the planetesimal hypothesis, the earth grew slowly into 
the state which it still in the main retains, dominated by working 
methods of the same order as those that now prevail. No radical 
change of working tenets between the formative and the subsequent 
stages is required. 
As already stated, the formative stages of the earth favored the 
retention within the earth-body of the stable crystalline compounds 
and the elimination of the unstable and mobile. It may be added 
that the formation of these stable compounds is favored by the con- 
ditions that lead to the eliminative process. These conditions were 
brought to bear on any given matter added to the earth first at 
shallow depths under moderate temperatures and pressures, and 
then successively at greater and greater depths, with higher pres- 
sures and temperatures, attended by the appropriate eliminations 
of unstable matter. This progressive action is held to distinctly 
favor the more and more perfect evolution of a crystalline earth- 
body progressively growing freer and freer of gaseous, liquefying, 
viscous, and colloidal elements. 
Now crystals are the very. type of elastico-rigid bodies. The 
permanent retention of their specific forms by means of definite 
elastico-rigid properties is one of their supreme qualities. We are 
not aware that there is any evidence that a crystal of rock 
undergoes any plastic or viscous deformation by reason of its own 
gravity in any known length of time. It may undergo change of 
form by molecular liquefaction and regelation or recrystallization, 
but it seems safe to challenge the citation of cases where crystals 
standing out from their attachments to the walls of crevices or 
cavities, though athwart the pull of gravity, have shown deflection 
or deformation, however long they may have stood in this position. 
The doctrine that flow will take place under gravitative stress if 
only time enough is allowed seems to be without the sanction of 
observation in this case, and equally without the sanction of sound 
theory when the nature of the case is precisely considered. The 
familiar reasoning is no doubt good for viscous bodies and for bodies 
in which a quasi-viscous condition can be induced by unbalanced 
