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NATURAL SCIENCES OF PHILADELPHIA. 129 



time they have been under my observation. Bird Shoals, the 

 most extensive of these, is believed to be now cuttino; in two ; 

 and it will probably in time form two islands, covered with vege- 

 tation, like the "town marsh," above mentioned as now lying be- 

 tween Beaufort and Fort Macon. A current directly across it, in 

 a line from Beaufort to the point of Shackleford, is already per- 

 ceptible during a part of each tide. 



The formation of the long, narrow islands that girt so large a 

 portion of the southern coast, is excellently shown here. Along 

 a considerable part of Shackleford and Bogue Banks the loose 

 sand is blown by the prevailing off-sea winds, and heaped up to 

 such extent, in some places, as to bury trees twenty feet high. 

 At other points the reverse action of the elements is witnessed, 

 in the stumps of trees, apparently cedars, that are denuded at 

 low tide. 



The general character of the shells that are so abundantly 

 strewn on the outer beaches, may be gathered from the list; of 

 these, as distinguished from those not likel^^ to be procured except 

 by dredging, the list is believed to contain very neai'ly all ; the 

 exceptions being chiefly such as only occur nearer Hatteras, al- 

 luded to in Dr. Stimpson's article. The abundance of fossil species 

 found on the beach, as the several Areas and others, is especially 

 noteworthy. I should judge that nearly half the number of indi- 

 vidual shells (not, of course, of the species) are not certainly 

 recent. In the harbor. Bird Shoals will be found the most fruit- 

 ful collecting-grounds when the dredge is not used. This is a 

 mile or so long, bj' half as wide, almost perfectly flat, alternatel}'' 

 covered with two or three feet of water and completely exposed. 

 The edges are loose and shifting, but most of the surface is some- 

 what fixed, and supports a slight sparse growth of marine plants. 

 This portion affords the best things. A considerable proportion 

 of the living shells of the locality may be found there. The sand 

 is full of tubicolous worms of several different species. Several 

 Echini, star-fishes, and jelly-fishes lie just about its edges. It is 

 the favorite spawning-ground of Limulus and two or three Busy- 

 cons. An Ascidian, an Ophiuran, Renilla reniformis, and Syn- 

 apta (?), are abundant. Two or three specimens of the rare Bran- 

 chiostoma were secured in sifting for Lingida pyramidata ; of 

 which last, as stated elsewhere, any desired quantity can easily 

 be procured 

 1871.] 



