246 
STRATIGRAPHICAL GEOLOGY 
around the Ozarks. Everton Formation, including also the med¬ 
ian limestone layers, was used in Arkansas for the lower part. 
As a basal sandstone this portion of the sequence was seemingly 
the only part represented by sediments in the north, in Iowa, 
Minnesota and Wisconsin. Probably the Arkansas name should 
now be restricted somewhat, and be made to designate only the 
limestone; and a new term proposed for the sandstones. 
The early correlations which are sometimes made between the 
Ozark and Lake Superior sections have to be taken with a great 
deal of caution. In new cycles of sedimentation special conditions 
have to be analized, the exact terranal equivalencies are not only 
uncertain, even when the lithologic similarity of sequence seems 
identical, but are especially misleading when long distances are 
not open for inspection and direct tracing from point to point 
in the field is not possible. 
The provincial Minnesotan Series of the Mississippi Valley 
therefore embraces (1) a basal Peter sandstone, (2) a median 
Everton limestone, and (3) a superior yet unnamed sandstone 
for which perhaps the Cap-au-Gres should be retained. The 
inferior unconformity merits closest scrutiny throughout the entire 
region from Lake Superior to Texas. 
Keyes. 
Extension of Triassic Coal-field of North Carolina. Important 
coal deposits of Triassic age prove to be more extensive than had 
hitherto been suspected. This coal-field known as the Deep 
River Basin lies mainly in Moore, Chatham and Lee counties. 
The entire northwestern side of the Triassic basin is now known 
to be underlaid by a commercial coal-bed 40 to 50 inches in thick¬ 
ness. In that portion of the seam which was opened up in the 
vicinity of Farmville and Cummock and which was extensively 
tested, there are, according to M. R. Campbell, not less than 
15,000,000 tons of excellent steam and coking coal; and the best 
estimates for the remainder of the field are at least 60,000,000 
tons available within depths of 1500 feet. 
Coal outcroppings are traceable for a distance of twelve miles. 
By means of drill-holes and shafts the coal is now proven into 
the center of the basin for a distance of one and a half to three 
and a half miles, at which line the seam passes below a depth of 
