3. Alnus is missing from all but two Trail Ridge samples, and then it appears as
less than one percent. The absence of Alnus makes the TR samples unlike
known Pleistocene deposits.
4. Taxodium pollen is present at very low levels in TR 2 especially, and Pinus is
low in TR 1 samples. These facts make the samples unlike Pleistocene deposits
from the Gulf Coast.

 The palynological composition of the Trail Ridge samples is equivocal as
regards the age of the deposit. This is unfortunate because all other means of
dating the ridge are equally ambiguous. Perhaps the one safe conclusion that can
be drawn is that, because no extinct species were identified in the TR samples,
and because oak pollen is not abundant in them, the peat and, therefore, the
ridge are not of Miocene age.

 SUMMARY

 Samples of dark brown lignitic peat were taken from beneath Trail Ridge, in
 northern Florida. Palynological analysis of the samples shows that a sub-tropical
 swamp composed mostly of small trees, shrubs, and aquatic herbs existed in the
 area prior to deposition of the ridge. The swamp developed near sea level on the
 reworked terrace sands of the Northern Highlands during Pliocene or Early
 Pleistocene time. As sea level rose, beach-ridge sands migrated laterally over the
 swamp and eventually killed and buried the plants and the peat they produced.
 The actual age of the swamp, and the age of Trail Ridge are difficult to
 determine except that neither appears to be of Miocene age.