BY W. N. BENSON. 575 



30 feet thick, and enclosed between two layers of banded chert. 

 On the hill, one-quarter of a mile east of this, is a second, more 

 richly fossiliferous band, which, however, is rather silicified, and 

 contains a good deal of tuffaceous material. This is inter-strati- 

 fied with the tuffaceous breccias of the Lower Series. Diphy- 

 phyllum, Heliolites, Heliophyllum, and Favosites occur here. A 

 little patch of white, saccharoidal limestone occurs in the bend 

 of the river, opposite Pyrke's Store, to the east, again, of these. 



Continuing southwards, there is a long series of small masses 

 either of clear pure lens, or patches of tuffaceous breccia with 

 large fragments of limestone; or, as these frequently are dissolved 

 out, the limestone-horizon is represented by merely tuffaceous 

 breccia, with large irregular cavities. The abundance of traver- 

 tine, in the creeks draining from here, indicates the fate of the 

 original limestone-content of these cavities. A small band of 

 dark tuff, with limestone fragments, appears by the roadside 

 south of Bowling Alley Point, the first limestone east of the 

 river; and two other small patches lie about one mile to the 

 south, on the hillside. In this case, the breccia is largely spilite. 

 Near by, is a small lens of pure, grey limestone only a few feet 

 wide. South, again, the limestone is present as fragments con- 

 taining crinoid and coral remains, imbedded in a dark, compact 

 spilite-lava, the microscopic examination of which gives every 

 indication of rapid cooling. Skeleton-crystals of augite, of mag- 

 netite, and felspar are imbedded in a glassy matrix. There can 

 be little doubt that here the organisms were killed out by a flow 

 of spilite-lava, which caught up and included the individuals. 

 The cavernous breccia and that containing limestone-fragments 

 were doubtless produced by a rain of volcanic material falling on 

 to calcareous organisms. Both indicate the very shallow water 

 origin of the rocks concerned, as was pointed out in a previous 

 noted*). 



This cavernous and limestone-tuff breccia occurs again just 

 north of Moonlight Hill, north of Swamp Creek. It is about 10 

 yards wide, and is bounded on either side by banded, cherty 

 claystones. It occurs in the same manner on the sharp point 

 north of the junction of Folly and Swamp Creeks. South of 



