80 Roper, on the Diatomacece of the Thames. 
these minute organisms were created to perform in the depo- 
sition of materials for the earth's surface, and stamp upon 
reflecting minds that no creature, even the most minute, is 
formed without special purposes ; and that the least in size of 
all, by the organization given to them by the great Architect 
of the Universe, have been employed to carry out his un- 
fathomable intentions.'' 
