BULL. GEOL. SOC. AM. 



VOL. 16. 1904, PL. 75 



Figure 1. — Slip-blocks from the Tucker Property 

 Showing rounded character of edges on natter sides and film of fiber on surface 



Figure 2.— Side View of Block Number 4 

 Showing sharp edge of the slip-block and the slicken-sided and film-covered surface 



SLIP-BLOCKS FROM THE TUCKER PROPERTY 



