INTRAFORMATIONAL PEBBLES IN RICHMOND GROUP 299 



vening troughs are about 2 . 5 inches deep, and the steeper slope 

 is on the western side. 



All of the strata included within the 30-foot section here 

 described belong to the Liberty formation. The lowest layer, L, 

 contains the characteristic fossil Dinorthis subquadrata, and Plec- 

 tambonites sericea is so abundant here that it suggests a horizon 

 not far above the base of this formation. The abundance of typi- 

 cal Strophomena planumbona throughout the section suggests the 

 lower half of the Liberty. Strophomena vetusta, associated with 

 Dinorthis subquadrata and Rhynchotrema capax, is comparatively 

 rare until the layers immediately overlying layer A are reached, 

 but the general aspect of the rock here still is that of the Liberty 

 formation. 



Judging from exposures on Graces Run, a little over a mile 

 west of Harshaville, the highest strata exposing ripple-marks occur 

 at least as far up as within 88 feet of the base of the Brassfield 

 limestone. Pebbles up to 6X4X0.5 inch in dimension occur at 

 a small fall half-way between this point and the mouth of Martins 

 Run, half a mile southeastward. Several pebbles occur also in 

 the wave-marked layers in the bed of Cherry Fork, immediately 

 west of Harshaville. 



The highest ripple-marked horizon along Elk Run, east of Win- 

 chester, appears to be about 80 feet below an exposure of Brassfield 

 limestone seen along the railroad, west of the creek. 



Pebbles up to 7X4X0. 5 inch in dimension occur also on Treber 

 Run, about a quarter of a mile west of the mouth of the stream, a 

 short distance west of the first crossing of the road following the 

 stream. Here the pebbles occur in large, loose slabs of limestone 

 containing a Liberty fauna, and evidently not transported far. 

 The pebbles consist of small-grained blue limestone, similar to those 

 occurring in layer G in the Elk Run section. 



Perhaps the chief reason why the presence of pebbles in these 

 ripple-marked strata has received so little attention is because they 

 are so readily overlooked. By far the larger number of pebbles 

 are horizontal in position, their stratification planes coinciding in 

 direction with those of the inclosing rock. Especially is this true 

 of the larger pebbles, while the smaller pebbles occasionally occur 



