MARKINGS, FOOTPRINTS AND FUCOIDS 315 



could be set to the advancing deluge. In a little time, how- 

 ever, he sees that the fiat, ' Hitherto shalt thou come, and no 

 farther,' has been issued to the great bay tide : its retreat com- 

 mences, 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 de- 

 position of the coarser sediment, — the lower side of each 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 salt 

 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. Man, however, carries the land - making process 

 farther ; and by diking and draining, excludes the sea water, 

 and produces a soil capable of yielding for an indefinite period, 

 without manure, the most valuable cultivated grains and 

 grasses." 



The mud of these great tidal flats is at the surface of a red 

 colour, and so fine that when the tide leaves it and its surface 

 becomes dry, it shines in the sun as if polished. It is thus 

 capable of taking the finest impressions. When the tide is in, 



