FORMATION OF BEACHES. 55 



ceding facts, to say, that all the northern part of this continent, at least all east of 

 the Mississippi, has been covered by the ocean since the drift period. For admit 

 that these waters rose 2000 feet above the present ocean, and how few mountains 

 even, would project above the surface. A few rocky islands only would be seen, the 

 largest around the White mountains and in the northern part of New York, while 

 the chief portions of the land would have disappeared : nor in the opinion of many 

 geologists is the evidence wanting, in the marks of drift agency everywhere, save 

 at the very top of Mount Washington, that all the hills, higher than 2000 feet, 

 save that single peak, were at that period beneath the waters. 



15. Admitting the existence of the ocean over the whole, or the greater part 

 of North America (and the same may be said of other continents, with similar 

 phenomena), and a gradual elevation of the land, or a depression of the ocean to 

 commence and continue to the present time, we can see how, by the drainage of 

 the uneven surface, and the action of waves, tides, and oceanic and fluviatile 

 currents, the whole system of beaches and terraces, as well as other forms of sur- 

 face geology, were produced. 



16. Let us begin with the beaches, which must have been formed the earliest. 

 As the elevated portions of the surface began to emerge from the waters, covered 

 probably to a considerable extent by drift detritus, the waves would act upon the 

 shores and comminute the materials, causing them to accumulate in bays and 

 friths. Yet at first the quantity, must have been small, both from the limited 

 extent Of coast, and deficiency of materials; and if the elevatory movement was 

 rather rapid, the fragments would not be reduced very small, nor thoroughly 

 rounded. Hence the highest beaches might be difficult to distinguish from the 

 drift, especially as the drift, while beneath the waters (I say nothing here of the 

 time or mode of its origination, save that the period was earlier than the rise of 

 the land), would most probably be made to assume a beach-form in some places. 

 If the elevation proceeded equably, the wave- worn detritus might be strewed some- 

 what evenly over the sloping surface, and not form distinct beaches. But if there 

 were pauses in the movement, we might look for beaches at successive levels. Yet 

 there would doubtless be great inequality in their position and character, nor 

 should we expect, unless the pauses were long, and the quantity of detritus great, 

 that they would form regular fringes around the islands : but rather that they 

 would be found in the successive bays that would be formed in different places, as 

 the irregular bottom of the sea emerged. 



I have supposed pauses in the vertical movement : and these doubtless would 

 produce beach deposits at successive levels. But when enough of land had 

 emerged to give rise to rivers, I think we can see how similar beaches might be 

 formed without paroxysmal movements. A river would carry detritus into the 

 sea, which might be spread along the coast by oceanic currents, and form a bank 

 beneath the waters. Gradually would this be raised by new depositions, and by 

 the uniform rise of the shore, until it would reach the surface, forming a marsh at 

 first; and as the process of elevation went on, a dry and raised beach, modified by 

 the breakers while within their reach. But when the river could no longer 

 deposit its sediment upon this bank, it would be carried forward into the water 



