BULL. GEOL. SOC. AM. 



VOL. 25, 1913, PL. 3 



LIMESTONE BOULDEES 



These seven boulders (slightly reduced) were flattened and etched by the solvent action of 

 meteoric water. Number 1 is very slightly affected. Numbers 2. 3. 4. 5. and 6 are arranged 

 to exhibit successive stages of flattening. Number »3 is nowhere more than three-sixteenths of 

 an inch in thickness. A transverse radial section of the upper right-hand margin of this speci- 

 men would show a slightly cuspidate ex;tension. This and number 5 both have etched furrows 

 following straight joint planes. Number 7 is a part of a boulder, from which more than one- 

 half has been etched away on one side, while the segment in the photograph, shown edgewise, 

 was preserved almost intact because it was securely lodged in a protecting matrix. 



