474 



SCIENCE. 



[N. S. Vol. II. No. 41. 



ten until the pipe reaches the underlying 

 sand, when the water at once rises to the 

 general water level, within 6 or 8 ft. of the 

 surface. (See Fig. 3, g and h.) 



Other duties prevented my mapping the 

 large number of ' bays ' that occur, to see 

 what relationship, if any, could be discov- 

 ered from their position. They seem to be 

 scattered irregularly over the flat surface; 

 some nearer the present coast than others. 

 Whether they ari-ange themselves along 

 certain lines I cannot say. 



By some the sand ridges are attributed 

 to wind action. This, however, would re- 

 quire a region free of vegetation, and we do 

 not know that this one ever was so over 

 any broad area. Besides, the wind would 

 pile the dunes on other sides of the ' bays ' 

 than the east and southeast, unless it blew 

 always from the east or southeast — a sup- 

 position of which no proof can be given. 

 Finally, wind action is insufficient to ac- 

 count for the bases of the sand ridges ex- 

 tending beneath the general surface of the 

 adjacent sands and clays. 



From an examination of the Coast Sur- 

 vey charts of the Albemarle and Pamlico 

 Sound region, I was at iirst led to conclude 

 that I had in the ' bays ' the results of nu- 

 merous repetitions on a smaller scale of 

 what is now going on in these sounds — the 

 difference in the size of the bodies compared 

 being great, but their agreement in j^i-ocess 

 being strong. Each sound is a drowned 

 valley with a bottom 15 to 25 feet deep at 

 most and, being cut off from the ocean bj' 

 the sand bar thrown across its mouth, they 

 are slowly silting up Avith the very fine 

 material brought down by the sluggish 

 streams that empty into them. If present 

 conditions continue long enough they will 

 be filled with a fine, compact clay, and are 

 already skirted on the southwest and east 

 by a sand dune. There is an apparent 

 analogy. The former sea where Darlington 

 now stands — though deep shortly before 



this from the thick beds of fuller's earth 

 which must have been very gently de- 

 posited far from shore sands — ^was shallow, 

 as is shown by the marl deposits near the 

 surface and by the sands over all the 

 region showing false or cross bedding and 

 containing in some places moderate sized 

 quartz pebbles. The shore line mvist have 

 been low. Streams were probably numer- 

 ous and small, no large drainage basins 

 having been formed. Allow time enough 

 for a little cutting of their channels by 

 these newlj'-born streams, then a very 

 small downward oscillation of the land,* 

 let the headlands be beaten off and bars 

 thrown across the mouth of the drowned 

 streams while the enclosed basin slowly fills 

 with fine sediment, and finally let the 

 whole region gradually rise as it has done 

 in fact, and we have a theory of their 

 origin (see Fig. 4). 



Fig. 4. Tlicordie Origin, a, soundlet being en- 

 closed; ft, headlands beaten-back; c, bar 

 thrown across mouth of sound. 



This theorj', however, is open to certain 

 objections. No remains of an old stream 

 channel entering this ' bay ' is found. The 

 existence of old beaten-off headlands on 

 either side has been asked about. If these 

 exist thej' are too faint to have made them- 

 selves noticeable when not looked for. 

 They may exist in the case of the larger 

 ones. The irregular distribution toward 



*See Prof. Shaler's 'Fresh Water Morasses, etc,' 

 10th An. Kept. V. S. Geol. Sur., pp. 330-331, for nu- 

 merous such oscillations recorded near this region. 



