GROOM : EFFECT OF FAULTS ON CHARACTER OF SEASHORE. 363 
included shale bands tend to form channels, and the sandstones minor 
ridges of varying breadth and distinctness, running out fco sea. 
Observation makes it clear that the existence of the relatively more 
and less elevated portions of the platform is due simply to the different 
rates at which denudation has taken place (the softer irregularly- 
broken beds being reduced to a lower level), and not in any way to 
the elevation or depression of faulted-blocks ; this will also be evident 
from a consideration of the nature of the dislocations. 
The channels, which intersect the rocks at varying angles are of 
some interest from the light thrown by them upon the effect of 
faults in facilitating marine denudation, and in modifying the con- 
figuration of the coast. When they are examined in detail they are 
seen to traverse nearly the whole of the plattorm between tide- 
marks ; towards high-tide mark they generally become less marked 
or slight, and the fault itself is often distinguishable only by a careful 
examination of the disposition of the strata on either side ; towards 
the sea they become wider and deeper, and form conspicuous fjord- 
like inlets (figs. 3, 3a), the lower parts of which are permanently 
filled with water. Still farther out to sea, they cut up the elevated 
sandstone reefs into small islets, sep .rated from one another, and 
from the mam land by channels of some depth (rig. 4). The chaunel- 
forming faults occur both as dip and strike faults, but faults crossing 
the outcrop of the beds obliquely are by far the most important. By 
the combined action of these faults the whole of the inter-tidal plat- 
form is cut up into a pavement, or mosaic, of angular blocks, the sand- 
stone portions of which project above the level of the rest as ridges, 
blocks, or islets. 
The smallest faults are planes of slight dislocation, along which 
the sea-water with its particles of sand can erode. In many cases 
the erosive action is facilitated by the irregular bending of the folia 
of the shale at the margin of the fault, so as to produce an easily- 
removed fringe of material. In the case of the larger faults the 
dragging action due to the horizontal displacement has produced, not 
a simple fringe, but a fringe traversed by lines, along which shearing 
or fracture parallel to the direction of the fault, has occurred. In 
many cases no definite fringe is formed, but planes of separation, 
C 
