PART FIRST. 
In proceeding to record the geological observations of 1857, I shall 
follow nearly my line of travel through the various counties from the 
north-east corner of the state, towards the west, and give the results of 
my observations under the heads of the different counties through which 
the geological corps passed. 
GREENE COUNTY. 
The so-called Chalk Bluffs form the extreme north-east boundary of 
Crowley’s ridge, where it abuts on the St. Francis river, a very short dis- 
tance below where that stream leaves tbe State of Missouri and enters 
Arkansas, and constitute, therefore, the north-east termina‘ion of that 
extensive ridge of land which extends from Helena, on the Mississippi, in 
Phillips county, through St. Francis, Poinsett and Greene counties, divid- 
ing the waters of the St. Francis from those of White river, and giving 
origin to the heads of the western tributaries of the former, and the east- 
ern tributaries of the latter streams. 
This ridge, so far as it has yet been explored, i. e., to the north line of 
township 10 north, is composed of, comparatively, very recent deposits, 
mostly of incoherent or but very partially indurated materials belonging 
to the age of the so-called quarternary formation, with the exception of a 
few very limited areas where hard quartzose sandstones of very ancient 
date protrude through these beds. 
The base of the quarternary deposits, forming the northern terminus of 
the Crowley Ridge, is a potter’s clay of considerable purity, and nearly as 
white as chalk; hence the name of the Chalk Bluffs, where this white clay 
is exposed on the banks of the St. Francis river, afew feet above low 
water of that stream, in the north-east extremity of Greene county. 
