been discovered in the lignites. In general, the amber 
which occurs in these deposits does not appear to have 
been reworked. 
In one site, at the base of a younger non-marine tuffa- 
ceous sequence, a single piece of amber was found in a 
bed containing numerous fragmentary and some marine 
fossils that clearly indicate reworking. Much of the bed- 
ding in this sequence suggests a lacustrine environment, 
an inference which locally is substantiated by the occur- 
rence of fresh water gastropods and charophytes. 
Hurd, Smith and Durham (1962) reported that studies 
of faunal inclusions, made in cooperation with more than 
50 participating scientists, have thus far revealed mem- 
bers of the following classes of animals: Myriopoda, 
Arachnida, Insecta, Mollusca and Reptilia. There are 
specimens representing one order of the Myriopoda and 
an anolid lizard among the Reptilia. Gastropods and 
pelecypods are represented among the Mollusca. The 
Arachnida, now known on the basis of ten families, are 
about equally divided between mites and spiders. The 
class Insecta, of which 15 orders have been recognized, 
is represented by 81 families. These include collembola, 
cockroaches, termites, earwigs, crickets, book lice, psy]- 
lids, leafhoppers, fugarids, true bugs, scorpion flies, 
thrips, dusty wings, caddis flies, moths, beetles, flies, 
ants, wasps and bees. It is obvious that some types of 
insects would be more prone to be trapped than others, 
and hence only a few of the many diverse insects that 
occurred in Chiapas at that time have been preserved. 
Somie types such as the stingless bees, now represented 
by only more than 100 individuals, probably were more 
easily trapped as a result of their habit of utilizing resin 
in their economy. Also ants are readily caught in exud- 
ing resin, but it appears that most of the other insects 
were trapped only fortuitously. In an examination of the 
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