and the variety of trees that are possible sources distin- 
guishes the Chiapas investigation from those of the Baltic 
wunber, as well as other deposits that are located at higher 
latitudes. In the latter cases, vast climatic and vegeta- 
tional shifts since the time of amber deposition preclude 
comparison with present conditions in the same area. 
Clues as to the kinds of plants that may have produced 
the resin, as well as to the composition of the forest, might 
be derived from several sources. ‘The most obvious source 
is the included plant remains. These consist of a few com- 
plete flowers, isolated floral parts, a few leaves, stellate 
hairs, seeds, pollen and spores and some cryptogams. 
Tapirira durhamu (Plate NLIV) and Acacia sp. have 
been described (Miranda, 1963), but most of the remain- 
der is stillin the process of being identified. No specimen 
of wood has yet been found immediately associated with 
the amber. Even the lignites, the woody material thus 
far has appeared to have been sufficiently decomposed 
by tropical weathering to be unidentifiable. Pollen in the 
lignites is being investigated as it may be of some signi- 
ficance in determining the forest type. The insects, when 
they are adequately studied, may suggest important habi- 
tat preferences, Just as they have in the Baltic amber. 
Pertinent data concerning the plant source of amber 
may be obtained from chemical and resinographic analy- 
ses of the amber and compared with similar analyses of 
known modern resins. Comparison of fossil with modern 
resins is inherently difficult due to oxidation and poly- 
merization in the fossilization process. Structural changes 
have taken place in the constituent acids, esters, alcohols, 
etc. The relative differences between the composition of 
resins in different genera may, however, be sufficient to 
find recognizable patterns. It is not feasible in this in- 
vestigation to attempt detailed organic analyses of the 
components of the resins and ambers. The previous 
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