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The second species of the same genus is the Bron- 
TozoUM SILLIMANIUM. Of this we have three speci- 
mens; the tracks have the same general character 
with the preceding, but are smaller. 
The third species of this genus is styled the Bron- 
TozouM Loxonyx, from 20%, a bow, and imi, a nail, — 
a curved nail. It is smaller than the Sillimanium, 
and has the nail set to one side. 
The fourth species, still smaller, is the Brontozoum 
Gracittmum. On this slab the impressions are in 
relief; viz.: Ist, of Brontozoum Gracillimum; 2d, of 
Brontozoum Parallelum; 3d, of the track of a tor- 
toise, fourteen inches long, and two wide. Other ex- 
tensive eminences and depressions, with rain-drops, 
may be observed on the same surface. 
The fifth species is called Bronrozoum PaRALLELUM, 
from the tracks being on a line with each other. Of 
this there are two specimens, one of them, however, 
being a single track. On the surface of the other 
slab there are at least five distinct tracks, one of them 
being a small new and undescribed species, — thus 
making the whole number of species of Brontozoum 
which we possess to be at least six. 
