= 
244 GEOLOGICAL RECONNOISSANCE 
CONCLUSION. 
It will be seen, on review of this Report, that the northern part of the 
counties lying north of the Arkansas river, are bounded by a, chain of 
mountains, which are crowned, on their summits, with massive conglome- 
rate or thick-bedded sandstones, locally pebbly, belonging to the millstone 
grit series. These massive sandstones are underlaid by reddish and dark- 
colored shales of great thickness, especially towards the south-east, as 
three hundred feet have actually been measured where they still extend 
beneath the drainage of the country. Thin seams of coal are found in 
the upper part of the dark shales, in all the counties from Crawford to 
Pulaski,* one of these veins appears to be persistent, and has been identi- 
fied, by its organic remains, over a great extent of country. Though 
often interrupted by extensive waves, which must have taken place 
in a great degree before the deposition of the superimposed sandstones, 
the general horizontality of the strata is well preserved. The axis of 
these waves appears to be parallel to the strike of the strata, and the 
elevated ranges produced from this cause are always capped with the 
millstone grit, with sometimes one or two hundred feet of shale over- 
lying it. After reaching the eastern boundary of Pulaski county, the dark 
underlying shales, with the incumbent sandstones, disappear either Ly 
dipping to the south-east, or what is most likely the case, they have been 
removed by denudation, and buried beneath heavy deposits belonging to 
the quaternary period. 
Permit me to take the present occasion, to acknowledge the many acts 
of kindness experienced at the hands of the citizens of the various countics 
through which I passed, which have promoted and facilitated the objects 
of the Survey. Where these are numerous and universal, it would be 
invidious to particularize individual caces. 
EDWARD T. COX} 
Assistant Geologist. 
* Though I did not see any coal in Pulaski, I was credibly informed by Mr. Elliott, that he had 
found a thin seam not far from the Kellogg mines; and he promised, if possible, to mect me at the 
mines and show it. 
