SECOND ANNUAL REPORT-SOUTHERN FLORIDA. 
183 
than those that break on the beaches during the other days of the year. 
On the west coast of Florida, south of the mouth of the Caloosa- 
hatchee River there are few dunes, and these do not face the open 
water of the Gulf. 
The dunes are composed of medium fine quartz sand, varying in 
tint from pale yellow to orange or to light reddish brown. This sand 
is rather angular and occasionally can be broken down to finer grains 
by rubbing between the fingers. Fossil shells are rare, if present at all. 
The writer in a rather careful inspection of several sections through 
dunes saw none. The varying tints of the sand are not according to 
the writer’s observations arranged in distinct bands nor is the sand 
everywhere plainly stratified. There is a tendency toward increase of 
color with depth below surface thus causing the coloration seen in a 
section through a dune to follow the surface contours. Also the 
shades of yellow and brown are frequently mottled or blotched. 
Streaks of gray sand, possibly caused by the decay of pine tree roots, 
extend a varying depth from the surface into the yellow and reddish 
sands below. In some instances toward the centers of dunes the sands 
may be so cemented by iron oxide as to form irregularly rounded 
masses of hard rock. 
Along the east coast the position of the more prominent dunes near 
the shore is indicated on the Coast Survey charts. A noteworthy suc¬ 
cession of ridges is the one that extends in an approximately north- 
northwest direction from two miles north of the dune, on which stands 
Jupiter lighthouse, at the north side of Jupiter Inlet, to and past Hobe 
Sound Station on the Florida East Coast Railroad. Just back of the 
station a summit of this series of ridges has a height of sixty-three feet 
above mean tide. Back of the lighthouse at Jupiter the top of one dune 
is perhaps forty-five feet high. Beyond Hobe Sound station the dune 
belt veers to the westward and dies away within three miles. There are 
no dunes along the railroad from Hobe Sound to the north line of 
Palm Beach County, and, according to report, no large ones north of the 
northern end of the Hobe Sound belt and no high ground between its 
northern end and Kissimmee. 
South of Jupiter Inlet dunes are numerous, but occur as discon¬ 
nected mounds or ridges, not as continuous or contiguous ridges. A 
typical dune forty-seven feet high at West Palm Beach, according to 
report, contained masses of rock. Isolated dunes and ridges near the 
shore between West Palm Beach and Jupiter are shown by the Coast 
Survey charts. South of West Palm Beach the dune belt lies farther 
inland, though generally parallel to the seashore, and the more promi¬ 
nent dunes have not been mapped. There is a fine dune ridge near the 
east side of Lake Osborne, about one mile west of Lantana Station. 
Isolated dunes of diminishing height occur to the south, the southern- 
