The classic concept of amber has been derived from 
the extensive deposits along the shores of the Baltic Sea 
which have been rather intensively studied for over a 
century. This Baltic amber is known to have been pro- 
duced in forests with a high proportion of subtropical 
to tropical floral and faunal elements (Czeczott, 1960: 
Schubert, 1958; 1961). Yet most comparative observa- 
tions of resin-producing trees and the manner in which 
they produced large quantities of resin that could be de- 
posited in the sedimentary record were restricted to cool 
temperate conditions around the Baltic Coast. Much 
emphasis was placed on the necessity for an extensive 
forest of trees producing resin excessively in response to 
diseased and physiological imbalance in order to accumu- 
late the incredible deposits that occur along the Baltic 
coast (Conwentz, 1890). Little attention was given to 
the fact that tropical trees can produce large quantities 
of resin under apparently natural forest conditions and 
that environments of deposition occur there that can 
favor large accumulations of resin. Unfortunately, it has 
been impossible to study the primary environment of 
deposition of the Baltic amber, because it is thought to 
be secondarily deposited (Czeczott, 1960). 
Amber from the Simojovel region, Chiapas, Mexico, 
is one of the occurrences in the New World tropics that 
provides sufficiently abundant material for detailed in- 
vestigation. Entomologists from the University of Cali- 
fornia at Berkeley became aware of the presence of 
numerous insects in this amber and initiated a collecting 
and study program in 1953 (Hurd and Smith, 1957). 
Although the occurrence of this amber has been recorded 
since at least 1891, the extent of the deposits and poten- 
tial biological significance of the material had not been 
known. The inaccessibility of this area in the southern- 
most state of Mexico and the possessive attitudes of the 
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