52 
GEOLOGY OF THE FOURTH DISTRICT, 
Sandy Beach and Stranded Shells. 
Among the interesting phenomena attending the deposition of the grey sandstone of the 
Second division, are the evidences of a sandy beach which was alternately washed by the 
advancing and retiring waves, and again left dry and above their reach. The proofs of this 
condition we find in the situation of the shells of Lingula, spread upon the surface, and the wave¬ 
lines, which mark the successive layers. 
In the open quarries at Lockport where extensive surfaces of the smooth layers are exposed, 
an observer will notice the shells of Lingula cuneata, curiously distributed, each with a little 
ridge of stony matter extending from the beak, narrowing and sloping down to the general 
level of the stone. 
The analogy of this little sloping ridge of stone to what we see formed in shallow currents, 
or where waves are washing a beach, and meet some obstruction, as a pebble, is too obvious 
to be mistaken; and the observer at once feels that he has discovered unerring marks of the 
course of the current, at the period when this rock was deposited. The beaks of the Lingula 
are all directed to the N.N.W. or varying from this to N. by W. half W. This perfect pa¬ 
rallelism, where hundreds may be seen on the surface of a single slab, is very striking. 
At first these shells appear as if they might have been living, and anchored to the sandy 
bottom by their peduncles ; but further examination has proved that they are all single valves, 
and must have been floated into their present situation, and strewed, by the waves or the current, 
evenly over the sandy surface. They all present the outer or convex side of the shell up¬ 
wards, and this is the position they would naturally take under the circumstances. After 
being thus left, and adhering firmly to the sand, the current or advancing tide swept over them 
again without the power of removing them from their position. The consequence would then 
be the production of a little ridge of sand, extending from the beak of the shell in the direc¬ 
tion of the current. 
JO. 
