THE ST. JOHN'S RIVER, FLORIDA. 



49 



SHAPE, SIZE AND COMPOSITION OF THE MOUND. 



The burial mound, 17 feet in height (spirit level and tape line measurement), 

 in circumference 478 feet, is conical in shape, save to the East, where from the 

 summit a gradual slope extends into a winding causeway or breastwork. 



The base of the mound is composed of shells, apparently brought from the 

 neighboring shell-fields to serve as a foundation in the marshy soil. 



Across the center of this layer of shells from north to south runs a ridge of 

 pure white sand. Above this ridge of white sand is a stratum of dark brown loamy 

 sand mingled with shells, while the sides of the ridge are rounded out with brown 

 sand in which shells are wanting, thus forming a symmetrical mound. At the cen- 

 ter of the mound the brown sand layer was 6 feet 2 inches in depth and the 

 white sand layer 5 feet 8 inches, leaving to the shell base a thickness of 5 feet 

 5 inches above the level of the margin of the base of the mound. In the northern 

 trench the white sand layer was encountered almost at the start. On the western 

 side it was found at a distance of 30 feet from the margin, while on the southern 

 side it began at 20 feet. 



As has been stated, a long and winding causeway joins the Tick Island mound, 

 which on this side, sloping to meet it, is much less steep than elsewhere. 



Mound and Causeway, Tick Island. 



In the rainy seasons, the territory surrounding the burial mound becomes soft 

 and swampy, and a causeway to the place of sepulture would prove of great con- 

 venience, and for this purpose the causeway probably served. The raised pathway 

 terminates at a large bean-shaped shell, or refuse heap, upon which and the adjacent 

 acres of shell-fields the Indians doubtless lived. 



