166 
JOUENAL OF THE GEOLOGICAL SOCIETY OF DUBLIN. 
part, the river with the ripple-mark on its bed is represented. The 
arrow indicates the direction of the current, and sedimentary layers, 
thinning out from the top towards the bottom, are shown on the shel¬ 
tered side of each of the ridges c, d. A few feet above the level of the 
river, in the adjacent bank, a laminated deposit of sand and clay is ex¬ 
posed, which also exhibits the ripple-mark, and appears to be the result 
of the river’s action at a former period. In some parts the laminse are 
homogeneous sediment, and are, therefore, of uniform thickness; but 
in general the layers are composed of partly fine and partly coarse 
materials, and present an attenuated profile from the crest of the 
ridge downwards, in a sloping direction, as at b , b'. Several ex¬ 
amples of unconformable succession are likewise visible, caused by 
the embedding of the newer upon the older laminae, as at u, a'. 
Dingle Bay. 
Fig. 2 is a section from the Silurian rocks of the county of 
Kerry, which occurs on the north shore of Dingle Bay, at Coosna- 
gloor, near the southern base of Mount Eagle, and is here introduced 
as affording an application of the foregoing principles to practice. 
In this locality all the strata dip in the same direction, namely, to 
the south, and might be mistaken for an entirely ascending series; 
but by reference to their sedimentary structure at e and/, a synclinal 
convolution was indicated for the first time, and afterwards proved 
to exist by a careful examination of the bedding. Enlargements of 
