1902.] N^TUEAL SCIENCES OF PHILADELPHIA. 655 



the forest at this place, a strip of higher ground runs out some 

 distance upon the meadow. The tension lines are well demarcated 

 here. Junipenis virginiana L. is the only tree wtiich borders 

 directly the sail marsh. A rounded dune occurs on the edge of the 

 marsh. From it a closer pro-pect of the salt marsh is to be had. 

 Jiiniperus virginiana L., Rhus glabra L., Mi/rica cerifera L., 

 Sassafras sassofras (L. ) Karst., Ilex opaca Ait., Rhus rudicans L., 

 with the climbing WilloughhcEa scandens (L. ) Kuntze form the 

 vegetal covering of this eminence. The outer zone of the salt 

 marsh is characterized by the presence of Hibiscus mo-cheutos L. 

 On the marsh proper occurs in several well-marked zones Dis- 

 tichlis maritima (L. ) Greene in the more elevated portions, while 

 Salicornia herbacea L., S. bigelovii Torr., Spartina patens (Ait.) 

 Muhl., and Limonium carolinianwn (Walt.) Britton grow in the 

 wetter areas. Along the edge of the thoroughfare^ through which 

 the tidal water circulates is found a pure association of Spartina 

 stricta (Ait.) Roth. The accompanying figure (fig. 5) shows the 

 zonal distribution of the salt-marsh plants on Seven-Mile Beach. 

 Near the outer edge of the marsh Hydroeotyle umbellata L. is 

 found, while on exposed sand slopes Opuntia opuntia (L. ) Coult. 

 is at home with a rose and a willow forming nearby thickets. 



Comparison of the Dunes at Piermont and at Sea Side 

 Park. 



The dune formation of the New Jersey coast, as previously men- 

 tioned, reaches its culmination at Piermont, where sand hills forty 

 10 fifty feet high are met with. The western slope of the 

 dunes at Piermont are precipitous, while the eastern slope (a 

 gradual incline) grades off into the lower dunes of the dune com- 

 plex. The dunes at Sea Side Park range in elevation from ten to 

 twenty feet, and the eastward or seaward slope is much the 

 steepest. The causes which have brought about this difference are 

 the following: The wave-made embankments on the sandy beaches 

 differ in their form and in the conditions of their construction from 

 those which are made up of pebbles.'' The sand, owing to the 

 fineness of its grains, is easily blown about by the wind. When 

 the tide retires, a broad expanse of this material is left for some 

 liours exposed to the sun. The surface dries, and the gales from 



« Also spelled thorofare. 



'Of. Shalek, Sea and Land, pp. 49-51. 



