884 The American Naturalist. [October, 
mains found in it were regarded as representing the earliest 
life on the globe. These remains were scanty, consisting chiefly 
of a species of Lingula as then understood (Fig. 1), and of some 
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Fig. 1. Lingula antiqua. 
The species for a long time 
supposed to be the oldest 
fossil on the globe, 
Fig. 2. Scolithus. A worm 
boring. 
straight, vertical tubes, at first regarded as seaweeds, but later 
on as the burrows of marine worms (Fig. 2 
Continuing in western Massachusetts the studies begun in 
northern New York, Dr. Emmons, in 1842, announced his be- 
lief that the Potsdam sandstone was not the oldest, stratified, 
fossil-bearing rock in North America, but lying beneath it, 
and therefore older than it, was a great series of sedimentary 
rocks for which he proposed the name “ Taconic.” It was not, 
however, until two years later, in 1844, that he described some 
fossils from this older series. Among these were two trilobites, 
and it is probable that more has been written regarding 
these two fossils than almost any others in the world, and in 
Figure 3 is shown one of them. These specimens were, of 
