We may say the bumps of which Mr. Talbot speaks are termed 'mud bumps,' from the fact of being composed of sediment. They present a curious spectacle as seen from a passing steamer. They are undoubtedly the result of subterranean pressure, but from what cause, whether volcanic, or the influence of the sea or river, or both, has not been determined. Many speculations have been entered into in regard to these phenomena, but as yet without fruitful result. Leaving this digression, we proceed to notice that the theories set up to explain the causes of the bars at the mouth of the river, have been numerous and various. Some suppose them to be the result of the water of the river meeting the opposing force of the Gulf waves, checking the current, and causing a precipitation of the suspended sediment. Others are of the opinion that the bars are entirely the effect of marine action, and endeavor to show that the immense inward flow of the Gulf washes up from its bed the vast accumulations that are continually forming in the way of navigation. After a personal observation and investigation, and as well after frequent and free consultation with others, we are persuaded to discredit the above-mentioned theories. The resistance of the Gulf does not form the bars, though it exerts an influence. The immense volume and force of water ejected from the river receives no immediate repellent action from the Gulf, but extends into it many miles without the least signs of disturbance, as may be plainly discovered even in the most casual observation. It is known as well that the water of the river remains perfectly palatable at a very close proximity to the sea. This is a very good evidence of the superior force of the river's current. The two volumes of water mix a considerable distance out at sea. An able engineer states that, upon examination, he found a column of fresh water seven feet deep and seven thousand feet wide, and discovered salt water at eight feet below the surface. As the result of his investigations, he divides the water into three strata, as follows: 1. Fresh water, running out at the top with a velocity of three miles an hour. 2. Salt water, beneath the fresh, also running out at about the same velocity. 3. A reflex flow of salt water, running in slowly at the bottom. It is this inward current, he thinks, that produces the deposit, and in doing so carries with it no small degree of sea drift. The influx of the lower column flowing up stream, after it passes the dead point, is allowed time and opportunity for the sediment to deposit. The principle of the reflex current is somewhat that of an eddy, not only produced by the conflict of two opposing bodies of water, but also is much influenced in the under currents by the multitude of estuaries presented by the irregular sea front of the coast.