CAHABA COAL FIELD: ACTON BASIN. 45 
the Millstone Grit formation. This cap or shield forms the 
rocks of the southeast slope of the Red Ridge, descending 
into the synclinal valley in the north part of the basin and 
ascending again in the anticlinal farther southeast. Arriv- 
ing at this point, it will be seen that the micaceous sand- 
stones and slates overlying the Millstone Grit begin to ap- 
pear, making the upper part of the Millstone Grit a good 
guide to assist in identifying the upper coal measures. 
After passing over various layers of sandstone, slaty sand- 
stone, and gritty slate with the Nunnally seam, the “ Five 
Group,” and the Harkness seam imbedded in them, we ar- 
rive at the large one hundred feet ledge of blue micaceous 
sandstone. This sandstone is very micaceous and is a great 
landmark in the identifying of the accompanying coal 
seams. Overlying this blue micaceous sandstone is the 
Martin seam, and about one hundred and fifty feet of lam- 
inated sandstone interlarded with thin layers of hard block 
sandstone, some of it breaking out in square blocks. Above 
this is the Whetrock seam and the overlying Wadsworth 
seam, and above and including the two just named is the 
whole productive group of seams up to the Helena seam. 
In the northeast corner of section 18, township 19, range 
2 west, I found some irregularities of the measures, with 
indications, however, that the fault was local, or not very 
extensive. I did not ascertain the extent of it, considering 
at the time that it did not merit a thorough investigation. 
The rate of dip of the rocks of this basin varies from 
3° or 4° in the north part of the basin on the Shades Moun- 
tain side, up to 85° on the southeast side of the basin adja- 
cent to the great boundary fault. 
In the southwest corner of the southwest quarter ‘of sec- 
tion 8, township 19, range 2 west, near the Samuel Acton’s 
house, the rate of dip was found to be 7°. 
On the Mad. Acton land in the southwest quarter of the 
northeast quarter of section 18, township 19, range 2 west, 
I found the rate of dip to be 15°. 
In the southeast corner of section 18, township 19, range 
2 west, on the T. J. Winfield land, found the rate of dip to 
be 19°. On the Acton seam close by, the rate of dip was 
21°; on the Mrs. Jane Acton land in section 20, township 
