18g0.] St. Louis Limestone. 307 
this case cannot be gainsaid; but that the shore line is always 
thus attended cannot be sustained by facts, The stress laid upon 
this feature of the St. Louis limestone by Worthen, White, and 
even Hall himself, is of itself sufficient to necessitate an addi- 
tional explanation of its cause. 
Another important feature of this limestone not yet noted, and 
one of great significance, is its odlitic character. In the Iowa 
Reports this is not mentioned by White, though noted several 
times in the detailed observations by Prof. Worthen in Hall’s 
Report of 1858, as also in the Illinois Reports. 
“ Above it becomes a regularly bedded light gray limestone, in 
strata from six to twenty inches in thickness, the upper layers 
having an odlitic structure.” * In the vicinity of Keokuk, Iowa, 
the semi-odlitic character may also be observed, though not 
especially prominent. 
In Illinois it was observed by Worthen at several localities : 
“Oolitic beds are quite characteristic of this division, and in 
Hardin county massive beds of odlitic limestone form the upper 
portion of it at several localities. . . - About three 
miles above Alton there are some odlitic tad wpa res beds in 
the lower part of the division, which are characterized by great 
numbers of small shells.” 4 
In Indiana the odlitic structure is especially prominent, occur- 
ring in massive strata twenty to thirty or more feet in thickness 
in the counties of Owen, Menge Lawrence, Washington, Har- 
rison, and Crawford. 
The quarries in these counties supply a most excellent building 
stone, which is becoming quite celebrated for its durability, as 
well as the facility with which it may be dressed to any desired 
fõrm. 
It* has been formed from the crushed remains of marine shells, 
corals, etc. These have been pulverized to the condition of fine 
sand, their soluble impurities washed away, and their insoluble 
residue reunited into solid rock by a deposit of carbonate of lime 
as a cementing. material. . . . . Its rich gray color, close 
S At Croton, Ia. Hall's Report, 1858, p. I91. ; tess 
* Illinois Report, Vol. I., p. 88. : k T ; 


