Correspondence. 1 9 1 
distinct members which in Stone county, Mo., may be described as the 
heavy bedded, gray Louisiana limestone proper, 20 feet thick; the green 
shale, 7 feet; the fossiliferous brown shaly limestone, 10 feet; and the 
speckled crinoidal limestone, 3 feet. These are all present at Eureka 
Springs, Ark., but the three last are much reduced in thickness, less dis- 
tinct in character, and have not received the attention which they de- 
serve. 
I wish to take advantage of this letter to remark that the persistency 
of the geological students of the lead and zinc district of southwest 
Missouri to set up and maintain an independent local classification of 
the rocky strata of this region is hardly called for. The "Cherokee'' 
limestone of their classification is, beyond doubt, the equivalent of the 
Augusta (Burlington and "Keokuk") of Iowa and Illinois, and the 
"Boone" chert, with the "St. Jo marble" added, is with equal certainty 
the practical equivalent of the Kinderhook group of the Iowa-Illinois 
district. These facts have been known for years, yet even to-day Joplin 
mining geologists will contend that such correlation is so doubtful that 
they are justified in setting up their own system of nomenclature. 
In conclusion, to rightly fix my relation to the study of the stratigra- 
phv of southwest Missouri, I will give a column of the strata in Stone 
and Barry counties, including the Eureka Springs district, as follows: 
1. Coal Measure sandstone, conglomerate and a little shale. 50 feet 
Marked erosion and non-conformity. 
2. Augusta, crinoidal limestone. 
3. Heavy bedded, sometimes magnesian, argillaceous, brown 
limestone (Kinderhook). 
4. Shaly limestone, greenish, calcareous shales and heavy 
chert layers (Kinderhook shale proper). 
5. Hard, evenly bedded, gray, sub-crystalline limestone 
(Louisiana proper). 
6. Green, thinly laminated, non-fossiliferous shale. 
7. Fossiliferous, brown, shaly limestone (part of St. Joe mar- 
ble of Arkansas). 10 feet 
8. Evenly bedded, speckled (brown and white) crinoidal 
limestone. 
9. Black Eureka shale. 
10. Yellowish Sylamore sandstone (with characteristic black 
quartz grains). 
11. "Cotton-rock" and sandstones of Ozark series. 
Numbers 3 to 8 inclusive are, beyond any reasonable doubt, the 
exact equivalents of the Kinderhook group of Iowa and Illinois, become 
less shaly and more highly calcareous and cherty toward the south- 
west from their type locality. Also, if lithology may have any weight 
in classifying strata, numbers 9 and 10 are distinct from the Lower Car- 
boniferous series and may be considered as Devonian in position, if not 
age. 
As mv studies in stratigraphy become more advanced as the years 
50 
feet 
30 
feet 
130 
feet 
20 
feet 
7 
feet 
3 
8 
feet 
feet 
4 
200 
feet 
feet 
