250 FreLp CoLumMBIAN MusEUM—GEOLOGY, VOL. I. 
originally regarded by Merrill, calcite. Theexact stages of the proc- 
ess by which vermiform stalactites of calcite would be produced 
seem to me, therefore, less evident than are those by which such 
stalactites of aragonite are formed. Yet, until we have better knowl- 
edge it may be a reasonable hypothesis to suppose that the same 

Fic. 1—Deposits produced by capillary attraction, on a stalactite, a glass rod and a glass tube. 
conditions which produce such forms in aragonite (supposing Senft 
to have correctly judged those conditions) viz.: deposition from 
dilute solutions in sheltered situations, may be regarded as those 
which would produce similar forms of calcite. Why, however, ara- 
gonite should be produced in one case and calcite in the other, I can- 
