BULL. GEOL. SOC. AM. 



VOL. 32, 1920, PL. 11 



Figure 1. — Characteristic Outcrop of a Dike, radiating from the laccolithic Cexter, 

 WEST OF Gold Butte Post-Office, ox Map, Figure 4 



The Colorado shales, in benches with tliin sills, appear on the right, with the north end of 

 Middle Butte in the background. 



Figure 2. — Dike Numrer 24, west of Gold Butte Post-Office. Figure 4 



This is a view of two dikes, crossed by a gulch following a fault, which offsets the front dike 



so as to open it like a gate. 



DIKES IN THE SWEET GRASS HILLS, MONTANA 



