42 GEOLOGICAL RECONNOISSANCE 



the valley of the branch on the north, has a sandstone near its summit, 

 which is probably the same sandstone seen in the base of the ridges on 

 Lafferty creek, and which is found at an elevation of 467 feet above low 

 water of White river, at Calico Rock, and was afterwards traced through 

 Izard county, to the high pine ridge, at the head of Sugar Loaf creek, and 

 which is usually marked by a growth of pine, as may be observed in plate 

 No. 1 of the Sugar Loaf mountain of Izard county, the site of that sketch 

 being on the plateau of that pine-bearing sandstone. 



No organic remains have yet been found in this sandstone, to indicate 

 its geological position; but, taking the lithological character and order of 

 superposition as a guide, it will probably be found to belong at the base 

 of the subcarboniferous series of Izard and Marion counties, resting on 

 limestones, which belong probably to the silurian period; it is, probably, 

 the equivalent of the " Saccharoidal standstone," of the Missouri report, 

 underlying the Cooper marble of the south-western part of that state. 



This sandstone seems to increase in thickness to the north-west, towards 

 the Lees mountain range. 



Two miles, from Calico, this sandstone is some 160 feet in thickness, 

 with perhaps some intercalated layers of limestone. Most of the beds of 

 the standstone, in this part of Izard, seem to be white or of pale yellow 

 colors, and soft. 



The dip is irregular, and often undulating, and conformable to the gen- 

 eral contour of the country. However, the prevalent dip is to the south- 

 west. 



The limestones of this region, are of light and dark grey hues, and often 

 singularly weathered into small furrows, radiating from a centre, and 

 often intersected with veins of calc-spar. 



The ridge of cellular buhrstone, which I passed over, before descending 

 to the North Fork, was found, by the aneroid barometer, to be 537 feet 

 above that river. 



Before reaching Athens, the Sugar-loaf mountain of the south-eastern 

 part of Izard county is in view, conspicuous above the intervening ridges. 

 [See plate No. 1.] 



At the mouth of the Pine bayou, the cliffs capped with sandstone are 

 about 200 feet. 



The soil of this part of Izard county, is best adapted for corn; it will 

 yield about 30 bushels to the acre of this grain; 15 of wheat, and about 

 the same of oats, and 800 pounds of cotton in the seed. The season for 

 cotton is rather too short in this high, northern part of Arkansas. 



The growth on the lands above cited is black-oak, hickory, and some 

 red-oak. The sample of this soil collected for analysis may be considered 



