166 ‘Geological Observations upon 
it has often been compared to a great canal, which occasionally pre- 
seats elevated banks, but generally cuts through level pine woods, 
having clean, gravelly banks, and thus presenting a marked contrast 
with southern rivers, whose sunken borders, so frequently offer a 
mere jungle of cane-brake, tall grasses, shrubs and trees. In Bar- 
tram’s travels in North America* we find the following account of 
this stream, and his explanation of the unusual transparency of its 
water. 
“ The Indians and traders say that this river has no branches or col- 
lateral brooks or rivers tributary to it; but that it is fed or augmented 
by great springs which break out through the banks. From the aec- 
counts given by them, and my own observations on the country round 
about, it seems a probable assertion; for there was not a creek or riv- 
ulet to be seen, running on the surface of the ground, from the great 
Alachua Savanna to this river, a distance of above seventy miles; yet, 
perhaps, no part of the earth affords a greater plenty of pure, salu- — 
brious waters. The unparalled transparency of these waters furnishes 
an argument for such a conjecture, that amounts at least to a proba- 
bility, were it not confirmed by ocular demonstration; for in all the 
flat countries of Carolina and Florida, except this isthmus, the waters 
of the rivers are, in some degree, turgid, and have a dark hue, owing 
to the annual firing of the forests and plains; and afterwards the heavy 
rains washing the light surface of the burnt earth into rivulets, which 
rivulets running rapidly over the surface of the earth, flow into the 
rivers, and tinge the waters the color of lye or beer, almost down to 
the tide near the sea coast. But here behold how different the ap- 
pearance, and how manifest the cause! for although. the surface of 
the ground produces the same vegetable substances, the soil the same, 
and suffers in like manner a general conflagration, and the rains, in 
impetuous showers, as liberally descend upon the parched surface of 
the ground; yet the earth being so‘hollow and porous, these supera- 
bundant waters cannot constitute a rivulet or brook, to continue any 
distance on its surface, before they are arrested in their course and 
swallowed up: thence descending, they are filtered through the sands 
and other strata of earth, to the horizontal beds of porous rocks, 
which, being composed of thin separable lamine, lying generally in 
obliquely horizontal directions over each other, admit these waters to 
pass on by gradual but constant percolation. Thus collecting and as- 
sociating, they augment and form little rills, brooks, and even subter- 
* Dublin, 1793, p. 223 et seq. 
