p3KEL.] ARKANSAS. 105 
Feet. 
. Sandy clayey chalk, whirl) contains great numbers of the fossil oyster 
Gryphsea vesicularis. These fossils are found in the marls some distance 
both above and below this formation, but in no other bed of rock in this 
region have they been found in such abundance. In natural exposures 
the chalk weathers from about them so that they usually almost cover 
the surface of the ground or are scattered in the soil. This shell bed at 
the base of the formation is such a marked feature that when it is once 
seen it may be easily recognized again. This shell bed crops at the north 
border of the Saratoga marl and throughout its extent 3-5 
The Saratoga marl is a massive bed of dull-bluish, sandy, chalky 
ock. Exposures do not usually show distinct bedded structure, 
ihough a slight variation in weathered surfaces may indicate the direct- 
ion of the dip of the rock. As the rock weathers it changes in color 
Tom dull blue to shades of grayish and creamy white. Its hardness 
md general plrysieal appearance are almost identically the same as 
hose of the lower sandy member of the Whitecliffs chalk. It breaks 
n rudely conchoidal flakes and crumbles at the tap of the hammer, 
jlmall pieces of the fresh rock may be broken by the hand and crum- 
led to dust between the fingers, but not without some difficulty. 
WASHINGTON AREA. 
The rock section is well exposed, as illustrated in the section. 
Section north of Saratoga. 
Feet. 
From the level of Saratoga down to Saratoga marl, surficial deposit of line 
yellow sand, about 40 
Saratoga chalk exposed in brink of hill north and east of Saratoga and in 
knob one-half mile north of Saratoga, lower beds of the formation 20 
Limy blue-clay marl 1 75 
This marl is exposed around the base of the hill at Saratoga, and in t he 
cultivated lands 1J miles north of the town it becomes gradually more 
chalky downward from the top to its contact with the chalk marl below. 
Bluish friable chalk marl 20-30 
This is the gradation bed from the blue marl above into the purer chalk 
below. 
White chalk in the Saline Landing area. 
Thick deposits of sand cap the hill at Saratoga, concealing all of the 
[halk rock except the lower beds in the slopes east and northeast of 
he town. 
Fe The lower part of the Saratoga chalk outcrops in a considerable 
•ea on Mr. Jones's place in the NE. i sec. 35, SW. i sec. 25, and 
)W. i sec, 36, T. 11 S., R. 27 W. The chalky oyster-shell bed at the 
20|ase of the formation is well exposed north, south, and west of the 
ouse, which is in the NE. £ of NE. i sec. 35. 
Samples of the chalk were taken from the top of the oyster-shell 
ed near the base of the formation, and are not physically different 
