THE LOMBARD OVERTHRUST AND RELATED FEATURES 275 



extending from near the southern border of the Fort Logan Quad- 

 rangle near latitude 46 to the double horseshoe bend. It consists 

 of evenly bedded, pale greenish shales with a few bands of quartz- 

 ite. The quartzite occurs in beds from 1 to 25 feet thick. The 

 formation is in apparent conformity with the overlying Cambrian 



Fig. 4.— Folded Madison limestone near southern end of ridge, north of Three 

 Forks. 



quartzite near the southern end of the exposure, but inasmuch as 

 the contact was traced for only a short distance an unconformity 

 with very slight angular discordance may have been overlooked. 

 Although the complete section of the Empire shale was not seen, 

 it is probable that 800 feet is a conservative estimate for the thick- 

 ness of the formation in this area. 



