40 BEVIEWS — ACADIAN GEOLOGY. 



had altogether retired from its bed ; and the distant channel appears as a mere 

 stripe of muddy water. At the commencement of flood, a slight ripple is seen to 

 break over the edge of the flats. It rushes swiftly forward, and, covering the 

 lower flats almost instantaneously, gains rapidly on the higher swells of mud, which 

 appear as if they were being dissolved in the turbid waters. At the same time the 

 torrent of red water enters all the channels, creeks, and estuaries; surging, 

 whirling and foaming, and often having in its front a white, breaking wave, or 

 l 'bore," which runs steadily forward, meeting and swallowing up the remains of 

 the ebb still trickling down the channels. The mud flats are soon covered, and 

 then, as the stranger sees the water gainiag with noiseless and steady rapidity on 

 the steep sides of banks and cliffs, a sense of insecurity creeps over him, as if no 

 limit could be set to the advancing deluge. In a little time, however, he sees that 

 the fiat, " hitherto shalt thou come and no farther," has been issued to the great bay 

 tide : its retreat commences, and the waters rush back as rapidly as they entered. 



The rising tide sweeps away the fine material from every exposed bank and 

 cliff, and becomes loaded with mud and extremely fine sand, which, as it stagnates 

 at high water, it deposits in a thin layer on the surface of the flats. This layer, 

 which may vary in thickness from a quarter of an inch to a quarter of a line, is 

 coarser and thicker at the outer edge of the flats than nearer the shore ; and hence 

 these flats, as well as the marshes, are usually higher near the channels than at 

 their inner edge. From the same cause, the more rapid deposition of the coarser 

 sediment, the lower side of the layer is arenaceous, and sometimes dotted over 

 with films of mica, while the upper side is fine and slimy, and when dry has a 

 shining and polished surface. The falling tide has little effect on these deposits, 

 and hence the gradual growth of the flats, until they reach such a height that 

 they can be overflowed only by the high spring tides. They then become natural 

 or sale marsh, covered with the coarse grasses and carices which grow in such 

 places. So far the process is carried on by the hand of nature ; and before the 

 colonization of Nova Scotia, there were large tracts of this grassy alluvium to excite 

 the wonder and delight of the first settlers on the shores of the Bay of Fundy. 

 Mau, however, carries the land making process farther; and by diking and drain- 

 ing, excludes the sea water, and produces a soil capable of yielding for an indefi- 

 nite period, without manure, the most valuable cultivated grains and grasses. 

 Already there are in Nova Scotia more than forty thousand acres, of diked marsh, 

 or "dike," as it is more shortly called, the average value of which cannot be 

 estimated at less than twenty pounds currency per acre. The undiked flats, bare 

 at low tide, are of immensely greater extent. 



The differences in the nature of the deposit in different parts of the flats, already 

 noticed, produce an important difference in the character of the marsh soils. In 

 the higher parts of the marshes, near the channels, the soil is red and compara- 

 tively friable. In the lower parts, and especially near the edge of the upland, it 

 passes into a gray or bluish clay called " blue dike," or, from the circumstance of 

 its containing many vegetable fragments and fibres, "corky dike." These two 

 varieties of marsh differ very materially in their agricultural value. It olten hap- 

 pens, however, that in the growth of the deposit, portions of blue marsh become 

 buried under red deposits, so that on digging, two layers or strata are found mark- 

 edly different from each other in color and other properties ; and this change may 

 be artiScially produced by digging channels to admit the turbid red waters to over- 

 flow the low blue marsh. 



