114 FLORIDA GEOLOGICAL SURVEY—FOURTH ANNUAL REPORT. 
15 to 18 miles. The land is rolling or hilly. The drainage is by 
small streams that cut across the “valley” and flow into Holmes 
Creek. The native growth is short leaf pine and hardwood trees. 
Orange Hill and Oak Hill represent the eastward extension of this 
type of country. 
Owing to the natural fertility Holmes Valley was settled early 
and is found referred to frequently in the early history of west Flor¬ 
ida. Williams in his publications on west Florida, as quoted by 
Smith, ^offers the 'suggestion that Holmes Valley represents an old 
lake bottom, this view being supported in the opinion of Williams 
by the persistent fertility of the land. The origin of the “valley” 
however is very evident. Erosion by underground solution has been 
more rapid in the northern part of the county where the limestone 
lies near the surface than in the central part of the county where, 
owing to its southward dip, the limestone lies at a considerable 
depth. Erosion has also been more rapid in the vicinity of Holmes 
Creek and the Choctawhatchee Eiver. The result is that the 
northern part of the county, which in earlier times stood at an equal 
or greater level, is now lower by possibly 50 to 100 feet in elevation 
than the central part of the county. This so-called valley is in 
reality the transition grounds or foot hills between the lower lands 
to the north and west and the plateau to the south. Erosion is 
constantly encroaching on the plateau from the north so that the 
escarpment line of the plateau is constantly retreating southward. 
Orange Hill and Oak Hill are “outliers” from the plateau. That 
is they are local areas, retaining their original height or nearly so 
notwithstanding the fact that the surrounding land has been eroded 
to a lower level. 
No better illustration of the effect of topography on soils can be 
found- than in this section of Washington county. The level plateau 
of the central part of the county permits the accumulation of the 
sands on the surface as the underlying formations disintegrate. 
This section is therefore a sandy pine country. On the border line 
of the plateau, Holmes Valley, where there is considerable slope 
the surface sands are removed as fast as formed or nearly so. The 
parent formation is thus brought to the surface, soil formation is 
accelerated and continuously renewed, which results in persistently 
fertile soils. The flat lands along the river represent almost com¬ 
plete degradation, and here the sands accumulate to a greater or 
lesser extent. 
That the plateau of the central part of Washington county is 
*U. S. 10th Census. Report on Cotton Production, pt. 2, pp 45, 1884. 
