234 THOMAS C. BROWN 
circular, oval, or irregular, and the individual pebbles are either 
flat or rarely curved. They occur in the conglomerate closely 
packed together and in all positions relative to the bedding planes, 
flat, edgewise, or inclined. The frequency with which these broad, 
thin pebbles occur on edge has given rise in certain localities to the 
name ‘‘edgewise’”’ conglomerate.’ 
Above these Cambrian limestones come a series of apparently 
unfossiliferous interbedded sandstones and limestones several 
hundred feet thick and very peculiar in character. The sandstones 
are composed of pure white quartz sand, extremely well rounded, 
and loosely cemented together by calcareous or dolomitic cement. 
Ordinary weathering conditions quickly remove this cement and 
the rock yields a thick mantle of sandy soil poorly adapted to agri- 
cultural purposes. On account of this character the region is 
locally known as the barrens. The interbedded limestones are of 
a peculiar character also. They are unfossiliferous in so far as they 
have been examined, and where they outcrop they stand up as 
hills above the adjacent sands. 
These interbedded limestones were apparently formed under 
the same conditions as those of the underlying series, because they 
contain in places layers with the peculiar flat pebble-like structures 
and scattered odlite grains. Certain beds have peculiar wavy 
structures which give to the rock an appearance somewhat like 
the fossil Cryptozoon, but it seems to be wholly due to a mechanical 
distortion by lateral compression of the thin beds making up the 
rock. Generally the contact between these interbedded limestones 
and the overlying sands is very obscure because of the rapid 
disintegration of the sandstone. In one case the transition was 
observed. In it the upper layer of limestone, about a foot thick, 
contained numerous flat pebbles and a few odlites scattered through 
it. This was succeeded by about two feet of very thin-bedded 
fine sandstone approaching shale in appearance, with numerous sun 
cracks or mud cracks distinctly preserved in certain layers. Then 
came the sand composed of extremely well-rounded sand grains. 
The next overlying formation is a limestone, sometimes sandy 
and sometimes shaly, carrying a rather scant fauna of Lower 
*Stose, Folio 170, U.S. Geol. Surv. 
