438 



E. STEIDTMANN ORIGIN OF DOLOMITE 



2. The pore s^^ace of the unfolded Mississippi Valley dolomites ranges 

 from a fraction of 1 per cent to 13 per cent or more. The limestones of 

 this region have about the same range of porosity (see tables 1 and 2). 

 If dolomitization by underground waters were a very general process, one 

 would expect limestones to have preserved their composition by virtue of 

 a low degree of permeabilit}^ 



TAr.i-K 1. — 7'oyo.s/7// of nolomilc hinld'uKj /S7;o//r.v 



Formation 



Age 



Lower MaguesiaL , . Ordoviciau 



Trenton Ordovician 



Niagara Silurian 



Niagara Silurian 



Niagara Silurian 



Niagara Silurian 



Niagara Silurian 



Niagara Silurian 



Niagara Silurian 



Cambro-Ordovician . 



Cambro-Ordovician . 



Cambro-Ordovician . 



Cambro-Ordovician . 



Cambro-Ordovician . 



Ordovician-Silurian 



Jlississippian 



Ordovician 



Locality 



Determined I 



^er cent of 







by 



pore space 



Bridgeport, Wis. . . 



. E. 



R. 



Buckleys. 



13.19 



Ducli Creek, Wis . . . 



E. 



R. 



Buckley. . 



1.04 



Wauwautosa, Wis . 



E. 



R. 



Buckley. . 



6.40 



Genesee, Wis 



E. 



R. 



Buckley. . 



1.12 



Lannon, AVis 



E. 



R. 



Buckley. . 



3.17 



Burlington, Wis. . . 



. E. 



R. 



Buckley. . 



8.32 



Knowles, Wis 



. E. 



R. 



Buckley. . 



4.43 



Marblehead, Wis . . 



E. 



R. 



Buckley.. 



. 77 



Sturgeon Bay, AVis. 



E. 



R. 



Buckley. . 



.43 



De Soto, Mo 



H. 



A. 



Buehler". 



6.717 



Jefferson City, Mo . 



. H. 



A. 



Buehler. . 



8.574 



Koeltztown, Mo . . . 



. H. 



A. 



Buebler. . 



9.99 



Jefferson City, Mo . 



. H. 



A. 



Buebler. . 



9.24 



Rolla, Mo 



. IT. 



A. 



Buebler. . 



13.00 



Bowling Green .... 



. H. 



A. 



Buebler. . 



10.62 



Sedalia 



. H. 



A. 



Buebler. . 



13 . 38 



Big Horn Mis 



W 



J. 



Mead'". . . 



1.31 



Table 2. — Porosliy of Liinci^tone hiiildimj Stones 



Formation 



Bedford . 



Age Locality 



Ordovician-Silurian Jackson, Mo. . . . 



Ordovician-Silurian Cartbage, Mo. . . 



Mississippian Columbia, INIo. . . 



Mississippian Hannibal, ]Mo . . . 



INIississippian Joplin, Mo 



Mississippian Noel, Mo 



Mississippian I'ierce City, Mo . . 



Mississippian Pboenix, Mo 



Mississippian St. Louis. Mo. . . 



Mississippian Springfield. Mo. . 



I'ennsylvaniau . . . . Breckinridge. . . . 



Pennsylvanian . . . . Kansas City, Mo. 



Peunsylvanian. . . . I'rinceton, Mo. . . 



Mississippian , Bedford, Ind. . . . 



Dete 



rmined Per cent of 







by 



pore space 



H. 



A. 



Bueblerii. 



.32 



II. 



A. 



Buebler. . 



1.34 



H. 



A. 



Buebler. . 



3.104 



II. 



A. 



Buebler. . 



5.031 



II. 



A. 



Buebler. . 



1.129 



II. 



A. 



Buebler. . 



.85 



II. 



A. 



Buebler. . 



1.239 



H. 



A. 



Buebler, . 



1.989 



II. 



A. 



Buebler. . 



7.30 



II. 



A. 



Buebler. . 



.92 



II. 



A. 



Buebler. . 



8.185 



II. 



A. 



Buebler. . 



9.148 



II. 



A. 



Buebler. . -, 



10.04 



[ 4.92 



Bl 



atchley 12 ... 



7-14. 



8 E. R. Buckley: Building stones of Wisconsin. Bull. 4, Wisconsin Geol. Survey, 

 ^ Vol. ii, 2d series. Missouri Bureau of Geology and Mines. 



10 Bull. Geol. Soc. Am., vol. 24, 1913, p. 621. 



11 Vol. ii, 2d series. Missouri Bureau of Geology and Miues. 



12 1st Ann. Rept. on Geology and Natural Resources of Indiana. 



