Rock Structures Resulting from Earth Movements . 507 
large wave has superimposed upon it waves of the second order * r 
upon these are waves of the third order and on these waves of 
the fourth order, and so on. Moreover, running across the most 
conspicuous waves, at various angles up to perpendicularity, may 
be other waves of an equally composite character. As observed 
from a ship at sea, the waves of the first order are so large and 
have such gentle slopes that they are often overlooked, while 
the steeper waves of the second order are noticed, because more 
conspicuous. Upon account of their small size the waves of a 
higher order than the second are usually unnoticed, as are also 
the waves of all orders which are transverse to the more con¬ 
spicuous set. 
If when stirred by a great storm the surface of the sea could 
in an instant be frozen we should obtain some idea of the com¬ 
plexity of the waves. We should see primary elevations and 
depressions of circular, oval, and lenticular horizontal sections, 
in different sets, crossing one another in various directions* 
and upon these would be other sets of waves of like complexity 
of the second, third, and fourth orders, and so on. 
The rock waves of the earth are of greater size and of equal 
or greater complexity than the waves of the sea. The rollers 
of the sea, when not wind-forced, may be compared with the 
long gentle folds of rock. At first sight they seem simple, but, like 
the rock folds, when observed closely they are found to possess 
secondary crenulations. At the other extreme are the highly 
complex waves running in various directions at the same time, 
formed by the shifting winds of a storm, by currents and tides, 
together. The sea in this condition may be compared with the 
rocks in which each set of primary folds has superimposed upon 
it folds of the second order, and upon these those of a higher 
order up to the ttth order. The smaller orders of folds are micro¬ 
scopic. Such complexly deformed rock folds are called-crumpled, 
plicated, or implicated. 
Deep-seated, homogeneous rocks, when deformed, flow in the 
same way as would a flat, thick cake of dough if subjected to 
stresses similarly disposed. In this change no particles, small 
or great, weak or strong, escape the effect of the pressure. All 
are deformed. In extremely closely folded stratified or hetero- 
