358 
GEOLOGY OF THE FOURTH DISTRICT. 
The closing of the outlets of some of these streams is owing to the diminished quantity of 
water flowing into the lake by their channels. This arises from causes before explained, and 
which are constantly operating. For many years previous to 1835, the lakes were all at a 
lower elevation, and this allowed the formation of bars and beaches at the outlet of streams 
which before opened by a deep channel into the lake. 
Some of the bays along Lake Ontario formerly admitted vessels for several miles, while at 
the present time they are partially or entirely closed. The beach formed at the mouth of 
Irondequoit bay has a narrow opening of three feet deep, while formerly it was a quarter of a 
mile farther east, and of a depth sufficient to admit sloops which took in freights at the head 
of the bay three miles distant. This bay is so situated, that it receives the abraded materials 
of the banks of the lake, both from the east and west. It is one mile and a quarter wide, 
gradually narrowing southward ; and it is separated from the lake by a sandbar or beach from 
fifty to two hundred feet wide, and rising from three to twenty feet high. The greater part 
of this beach has accumulated within the last fifty years. At that distance of time, it was 
very low, and scarcely covered with grass ; it is now overgrown in some places with large 
trees. The sand and silt brought down by the stream into this bay are gradually filling it up, 
and eventually it will become a marsh, with the stream winding through it to the lake. 
The Twelve-mile creek, in Niagara county, presents a somewhat similar case. After the 
junction of the two branches, it runs in a deep broad channel nearly parallel to the lake shore 
for some distance, and its outlet is entirely closed with a beach of sand and pebbles. When 
the water accumulates so as to render the stream impassable, a channel is cut through the 
beach, which, from the greater flow of water, is kept open for a few days, when it again 
closes. The water in this channel, for two miles from the lake, is thirty feet deep, and ves¬ 
sels formerly entered here and loaded at that distance from the lake. We have here a re¬ 
petition of the same circumstances as at Irondequoit bay. The diminution in the quantity of 
water has doubtless been one great reason for the closing of the outlet; for had it been 
greater, the outlet would have been kept open. 
These are a few of the simple operations which, some centuries hence, will leave all this 
marshy region dry land, bounded by long ridges, the ancient beaches of the lake, through 
which the diminished streams will have made their way as in the ancient ridge which is now 
some miles distant from the lake. The same will eventually take place in all the lakes, though 
the process is so slow as to be scarcely perceptible. But we are to remember that the opera¬ 
tions of nature are the same, and the causes never cease ; so that if from analogy we prove 
that all this change has taken place, then by the continued existence of the same causes, we 
can anticipate, in a partial degree, what is still to result where the same materials are the 
subject of the experiment. 
