240 2=©=———s«. Coan on the Eruption at Hawaii. 
as described in vol. xx, p. 22 of this Journal. The shell is 
found in the same coarse grit as the Clathropteris, immediately 
beneath the trap (see section in the paper just referre : 
y referring to Bronn’s Letheea Geognostica, I find that the 
Rudiste with the exception of the genera—Orbicula and Cra- 
nia, are confined almost wholly to the Chalk Formation, and 
the shell from Mount Tom certainly comes nearer to the 
creeping, like fiery serpents, in a thousand gory looking rills, 
over the smouldering masses of lava, long ionae ited “These 
* From a letter to J. D. Dana, dated Hilo, March 7, 1856. 
