Feb. igoi. Observations on Indiana Caves— Farrington. 259 



with those under discussion. If it be considered further that varia- 

 tions in the form of a stalagmite may result from variations in the 

 rate of evaporation and content of carbonate of lime of the water 

 which produces it, further reasons for the peculiarity of form will be 

 added. Thus, if evaporation is rapid, or the content of carbonate of 

 lime high, so that a large quantity of the salt contained in each drop 

 is deposited at the top of the stalagmite and little is left to be 

 relinquished in the subsequent course of the water down the sides, a 

 long, slender stalagmite will be formed. If, on the other hand, 

 evaporation is slow, or the content of carbonate of lime low, so that 

 deposition will take place about equally during the course of the 

 water over the stalagmite, a broadly conical stalagmite will result. 

 It is evident that such variations occurring during the growth of any 

 single stalagmite would find expression in corresponding forms in 

 different parts of the stalagmite. 



Another form of stalagmite so far as I know peculiar to this cave 

 is that of a flattened cone. Such are the stalagmites known as " Mt. 

 Vesuvius" and the "Diamond Dome." The form is illustrated by 

 Fig. 2, PI. XXXII, showing a stalagmite collected by the writer at the 

 cave. I have indicated above in what manner slight evaporation as 

 compared with the rate of flow of water or a relatively low content of 

 carbonate of lime might be expected to produce such a form. It may 

 be further noted that the lateral surface of these stalagmites, instead 

 of being smooth like that of the ordinary stalagmite, is built out in a 

 series of sinuous walls running more or less horizontally around the 

 cone. These walls form numbers of little pools usually filled with 

 water and containing delicate crystalline aggregations of carbonate of 

 lime. The low slope of the surface allowing slow movement of the 

 water over it is doubtless responsible for the construction of these 

 walls. 



Stalagmo-Stalactite8. — Usually in the growth of cave formations, 

 a stalactite forms above its counter stalagmite. An odd reversal of 

 this condition of things so that the stalagmite forms above the stalac- 

 tite is to be seen in several instances in this cave, the formation 

 known as the " Mermaid " being perhaps the best example. Such 

 stalagmo-stalactites are formed by a drip taking place on the edge of 

 a limestone shelf so that the water which builds up the stalagmite, in 

 pursuing its further downward course forms a stalactite as well. Of 

 the general appearance of such formations Fig. 5, showing a speci- 

 men collected in Shiloh Cave, will give a sufficient idea. 



