POSITION OF SLATE HILL SHALES. 329 



believed to occupy the axis of the syncline. If that be true, the following 

 exposures may be of interest, since they lie east of the sandstones and 

 conglomerates which are nearer the western Newport road. 



A number of exposures of coarse quartzitic conglomerate lie a 

 quarter of a mile directly south of the ridge, and south of an east-west 

 road. Their strike seems to be north-south. 



Three-quarters of a mile southward, in the Portsmouth camp-meeting 

 grounds, coarse conglomerate is exposed, interbedded with sandstone. Strike 

 N. 7° W., dip 70° W. This exposure seems to lie on the eastern side of the 

 syncline. 



Southward no more coarse conglomerate is exposed. The next exposure 

 lies a mile southward, south of the next east-west road, on the west side 

 of the hill. Near the base of the hill occurs bluish-green sandstone with 

 narrow streaks of pebble layers, the pebbles being of very small size. 

 Farther east bluish-green shale is exposed at several points. This shale 

 resembles the greenish shales described as occurring beneath the sandstones 

 and conglomerates on the west side of the syncline. Their occurrence in 

 the same position on the east side is significant. Strike north-south, dip low 

 westward. 



RELATIONS TO SLATE HILL SHALES. 



It will be seen that the structure of the northern third of Aquidneck 

 Island is that of a syncline, the great mass of the rocks being dark carbona- 

 ceous shales, and to a less degree sandstones. Overlying these, near the 

 top, is a thin series of greenish shales, and a remnant of a conglomerate 

 series overlying the green shales is still preserved in places near the 

 middle of the syncline. A little over two miles south of the green shales 

 above described, from the east and west sides of the syncline, the green 

 shales of Slate Hill begin. The synclinal structure is no longer apparent 

 so far southward. Instead of the single syncline of the northern third of 

 Aquidneck the southern third shows at least three synclines — one east along 

 the Sakonnet shore; a second, the southward-plunging syncline in the 

 Paradise Rock series and west of Eastons Point; a third, just west of 

 Miantonomy Hill and in the Coasters Harbor Island region. 



Possibly the green shales near the top of Slate Hill represent the 

 place where the marked southward pitch of these more southern synclines 



