TATE— ON THE GEOLOGY OF BBADNELL. 
65 
Other conditions of the Carboniferous Era are made known by 
several of the sandstones, which present ripple-marks, oblique lamina- 
tion, and fossil worms and worm-tracks, indicating ancient beaches and 
the action of waves and currents. When deposits are made in com- 
paratively tranquil water, the planes of the several beds are pretty 
nearly parallel to each other ; but some sandstones exhibiting in mass 
this ordinary stratification have also included in them thin layers or 
stratula, which are inclined sometimes highly to the plane of the 
principal bed ; of this oblique lamination, or, as it is frequently called, 
false-bedding, there are many examples in the " Beadnell-sandstones." 
Both ripple-marks and false-bedding result from the action of waves 
and currents ; the former being produced by the gentle motion of 
waves, and the latter by stronger currents. After the recession of 
the tide, furrows and ridges may be seen on sandy and muddy coasts ; 
these are similar in form and arrangement to those left impressed by 
ancient waves on the " Beadnell-sandstones," in which they are beau- 
tifully distinct ; some of them are large, measuring six inches from one 
ridge to the other, and they usually trend from east by south to west 
by north. As the line in which a current moves is at right angles to 
the direction of such marks, the ancient currents which rolled over the 
Beadnell coast must have come either from the north or the south. 
Mr. H. C. Sorby has attempted to determine the direction whence 
currents came by observations on the dip of the stratula, as he con- 
siders the direction to be the opposite to this dip in relation to the 
plane of true bedding ; and he concludes from a series of observations, 
that the drifting cun-ent which formed the carboniferous sandstone- 
beds of the southern part of the coast of Northumberland came from 
north 9° east.* The " Beadnell-beds," however, do not not lead to any 
such general conclusion, for I found in the same stratum, and within 
a distance of not many yards, that the stratula in one place dipped 
from 40° to 70° to the north, and in another place at similar angles to 
the south-west by south. Probably this bed had been formed by the 
action of strong eddies and counter currents, which piled up the 
drifted sand with considerable irregularity. 
Most curious and instructive are the fossil worms and their tracks 
which occur in several layers of flaggy and ripple-marked sandstones 
* Proceedings of the Yorkshire Geological Society for 1852, p. 2.32. 
VOL. II. P 
