218 



IRVING. 



The conditions at the Badger shaft indicate that there has 

 been a fault along the northern limits of the mountain, and the 

 curved phonolite bluffs on the east and southwest make it seem 

 probable that large blocks of the overlying rock have been 

 lifted by the broad flat eastern mass, as by its smaller western 

 prototype. From the steep inner border of the crater-like de- 

 pression on the north, we would infer that the limestone was 

 not as far uplifted within its confines, but that the fracture on 

 this side of the hill was of a circular character. The rock 

 was allowed to enter it, and to form the in-curving, dike-like 

 arms that are so conspicuous a feature. The mass of lime- 

 stone in the depression was large and heavy, and as the force 

 of intrusion could expend itself lifting the smaller masses it did 

 not attain so high an elevation. If we consult the diagram- 

 matic section on Fig. lo, which is supposed to have an east and 



Fig. lo. East and west section of Ragged Top mountains across crater-like 

 depression on the southern slope. 



west direction across the depression, these relations will be 

 clearly illustrated. 



Taken as a whole the Ragged Top laccolite forms a strik- 

 ing contrast to Sugar Loaf hill. The latter is intruded at the 

 base of the Cambrian, and is comparatively flat and low-lying ; 

 the former lies almost immediately below the limestone and 

 owes its ragged aspect, to the massive character of that rock. 



