Ill 



and to the encroaching demands of railroads and industrial en- 

 terprises using sand for ballast or building purposes. 



At Beach, 111., four miles north of Waukegan, there remains 

 a narrow strip of shore dunes upon what was, doubtless, origi- 

 nally a sand-bar thrown up by the lake. Back of this strip lie 

 the channels, and the many bars and shallows of Dead River 

 Flats. The shallows are always swampy and in wet seasons usu- 

 ally flooded so that the dune strip has a fresh water sea at its 

 front and a fresh water swamp at its back, these conditions much 

 resembling those prevailing at Seven-mile Island, N. J., except 

 that in the latter case the water is salt and disturbed by diurnal 

 tides. Lying under north latitude of about 42° and subject to a 

 summer temperature of 63-77 F., this area has a summer rain- 

 fall of ten to twelve inches and a total annual precipitation of 

 thirty-three inches. The prevailing breeze is from the southwest 

 but it is the occasional strong wind from the east or northeast 

 which drives the beach sands landward to form the dunes. 



The characteristic plants upon the upper beach are: the 

 beach pea, Lathyrus maritimus, the sea rocket, Cakile edulenta, 

 the beach grass, Ammophila arenaria, and the beach reed, Cala- 

 movilfa longifolia, the last two serving most successfully as sand 

 binders in early dune formation. Upon the exposed changing 

 crests and fore dunes are also the sand cherry, Primus pumila, 

 the bear berry, Arctostaphylos uva-ursa, the creeping juniper, 

 Juniperus procumbens, the shrubby juniper, Juniper us com- 

 munis, var, together with the summer grape, Vitis aestivalis, 

 and the poison ivy, Rhus radicans. 



The forest association upon the lee slopes, from which most 

 of the species found upon the fore dunes appear to have been 

 derived, is now much thinned out. It is made up largely of these 

 distinctive species: the oaks, Quercus velutina and Q. alba; the 

 choke cherry, Primus virginiana; the two junipers, J. procum- 

 bens, and /. communis, var.; the bear berry, poison ivy and the 

 summer grape. Patches of the prickly pear, Opuntia Rafinesquii, 

 are not infrequently found in this association. The white pine, 

 Pinus Strobus, which formerly appeared scattered along the 

 stabilized dunes has practically been exterminated north of 

 Dead River outlet. 



At Seaside, Oregon 



The third locality under consideration lies on the Oregon 

 coast about twenty miles south of the mouth of the Columbia 



