INTRAFORMATIONAL PEBBLES IN RICHMOND GROUP 297 



Ft. In. 



Layer H. Crest of ripples running N. 15 W. 



Interval 5 



Layer I. Crest of ripples running N. and S., faintly defined. Near 



home of E. E. Jamison. 



Interval 5 



Layer J. Poorly denned ripple-marks, at next house on west side of 



creek. 



Interval 1 



Layer K. Crest of ripples running N. 70 E. 



Interval 1 



Layer L. Crest of ripples running N. 50 E. 



The fine-grained pebbles first described, apparently consisting 

 of a lime mud, supporting incrusting growths of Protarea, Dermato- 

 stroma, and various species of bryozoans, are specially characteristic 

 of layer D. This layer is exposed at several localities along the 

 creek, but the pebbles are common only southeast of the home of 

 Charles Bailey, on the eastern side of the creek. Here the pebbles 

 rest upon the top of the layer or are more or less imbedded in its 

 upper part. This pebble-bearing layer is exposed also farther up 

 stream, about 500 feet north of the road bridge. Here the pebbles 

 vary from 2 to 4 inches in length, and from a quarter to half an 

 inch in thickness. Farther up stream, immediately south of the 

 road bridge, this layer is strongly ripple-marked, the crest of the 

 ripples running N. 40 W. One pebble was noticed here 14 inches 

 long, 7 inches wide, and half an inch thick. Farther north, where 

 the pebbles are abundant, ripple-marks are absent. 



The less fine-grained and more angular blue limestone pebbles, 

 described last, occur in layer G. This layer is exposed between the 

 railroad bridge and the road bridge, a short distance northward. 

 The crests of the ripple-marks vary here (Figs. 1 , 2) between N. 3 W. 

 and N. 15 W. in direction, and on the average are about 30 inches 

 apart. The following pebbles were noticed here, imbedded within 

 the upper part of the ripple-marked layer, only the upper surface 

 being exposed. In each case the length, width, and thickness of the 

 pebble are given. One pebble, 4X3X0.5 inch, lay in a trough 

 and sloped gently toward the west. Another, 12X7X0.5 inch, 

 lay in a trough in a horizontal position. Two pebbles, 4X4X0. 25 

 inch, lay in a trough and sloped toward the east. Two pebbles, 



