GEOLOGY OF GILES COUNTY, VIRGINIA 
327 
29. Grayish blue limestone layers above shale parting two 
inches to three feet in thickness. Joints are vertical but not at 
right angles to the bedding. Other joints give sharp angles. 
There are calcite veins and a little chert. There are several 
shale partings with cross bedding in the lower layers, but the 
third layer is leveled up. Lower layers have conchoidal frac- 
ture. Rock is fine grained to fine crystalline. Weathers to bring 
out the bedding. 34 feet. 
30. Group of gray to brownish thin layers of quartzitic sand- 
stone, with shale below. 2 to 4 inches. 
21. Blue to blue gray, fine grained siliceous limestone, with 
much black and grey chert. One layer of the chert toward the 
top is nearly continuous. The unit has a hackly fracture with 
little jointing. Many calcite veins weather in relief. Weathers 
buff, brown and black. ' 3^/2 feet. 
32. Felsitic to fine crystalline massive, bluish, limestone be- 
coming lighter above. Bedding is not clear but is developed by 
weathering in the upper portion. In crystalline layers the cal- 
cite weathers out and feels like sand on the surface. Calcite 
veins weather in. Much black chert in layers of nodules. Joint 
ing is rare. Top layer seems to be wave marked as well as others 
and there are some thin shale partings on the wave marked sur- 
faces. Weathers a reddish brown to nearly black. 24 feet. 
33. Several limestone layers similar to 32 but thinner 
bedded, capped by a thin bed of bluish to reddish shale a few 
inches in thickness. In some places the shale contains chert and 
limestone pebbles as if residual. 11 feet. 
34. Series of broken limestone beds similar to 33 with three 
small faults of a foot or so-. Solution work and a filled sink 
hole are present. The filling is chert, clay and sandstone pebbles. 
White chalcedonic chert in the lower part. There are two shale 
partings near the top about a foot apart. 29 feet. 
35. Gray, rather massive, uneven bedded, finely crystalline 
limestone except three feet from the top where it is coarse. 
There is a pink layer two to four feet from the bottom. There 
are peculiar pits on the surface about six feet from the bottom. 
Weathers lighter than the stone to buff, not red. Calcite veins 
and nodules. Wave marks with a shaly surface at the base. 
20 feet. 
