The samples from Mina de Naranjo (X and XI) are 
presumed to be roughly the same age as in the Mina Palo 
Blanco sediments. Samples X and XI are similar in the 
relatively low percentages of Rhizophora pollen present 
and in their poor preservation. Only a few grains in each 
sediment could be confidently placed in one of the two 
major divisions. ‘he remainder were placed with those 
of uncertain affinity, but most grains belong probably to 
the Rhizophora spp. group. In Sample X, fungal spores 
were present in low percentages, and the majority of the 
pollen were unidentified tricolpate and monocolpate 
types. There were 7% fern spores. Pollen of Podocar- 
pus (Plate XLII, fig. 2) occurs infrequently in these 
sediments. Podocarpus is the only conifer present, other 
than a few poorly preserved grains probably of Pinus. 
Sample XI contained a somewhat larger percentage of 
Rhizophora pollen, including a number of Rhizophora 
spp.-type grains, and a considerably larger percentage 
of fungal spores. ‘The percentage of Mngelhardtia-ty pe 
decreased to 8%, and the number of fern spores remained 
high (7%). The depositional environment of these sam- 
ples is not suggested on the basis of their pollen content. 
The low percentages of Rhizophora might be interpreted 
as indicative of deltaic deposits such as those investigated 
by Muller (1959, Pica E), or of foreshore deposits. The 
generally moderate to high percentages of fungal spores 
in these sediments and the Palo Blanco samples above, 
according to the ideas of van der Hammen (1963), seem 
higher than those which would be expected in an off- 
shore environment; many more data from modern depo- 
sitional environments, however, are needed here. Amber 
from these deposits does have impressions of marine gas- 
tropods, which again suggests that the resin-producing 
trees were close to the shore so that the resin was de- 
posited in the water (or on the strand line with the shells) 
before it hardened. 
[ 319 ] 
