52 The American Geologist. juiy, looi. 
By paralleling- the g^eneral sections, the exact strati^raj^hical 
relationships of the various formations niav be clearly repre- 
sented. 
WINSLOW, 1896. KEYES, 1895. 
Potosi limestone 
St. Joseph limestone 
La Motte sandstone 
Iron Mountain conglomerate 
? 
Le Sueur dolomyte 
Fredericktown dolomyte. 
La Motte sandstone 
The names defined by ^^'inslow were incidentally men- 
tioned by him a year prcviotis* to the ptiblication of his de- 
scriptions, but at that time without definition. When they 
were formallv proposedt another set of names had been de- 
fined for the same reg^ion. 
Stratigraphically, the Iron Mountain conglomerate cannot 
be considered as a distinct geological terrane, unless the orig- 
inal signification of the title be wdiolly changed and restricted 
to the cong^lomerates encircling the peak of Iron mountain 
alone. On the same horizon of tmconformity and over a large 
area, similar conglomerates occur. These beds are not only 
not continuous, but they are often wddely isolated and tisually 
of very local extent. Moreover, if it were desirable to have a 
name undefined stand for this conglomerate the term stiggested 
would have priorit}' in another sense. It was tised with defin- 
ite application to the porphyry of the region.:}: The recogni- 
tion of the porphyry as a distinct formation is all the more 
significant since it has been found that it is really the upper part 
of the general granite mass of the area.S The conglomerates 
when they occur may be properly reg-arded as local basal facies 
of the La Motte sandstone. 
In both of these sections mentioned above, the stratigraphical 
delimitation of the La Motte sandstones is essentially the same. 
The same is true, to all practical intents, of the Fredericktown 
formation. Regarding the title St. Joseph that is used in the 
bulletin [j of the Federal survey, it may be said that the defini- 
tion of the formation was not jmblishcd until a }'ear after that 
'Missouri Geol. Sur.. voV vi, 1895. p. 331. 
jBull. U. S. Geol. Sur , No. 132. 1 S96, ]). 11. 
i-Vi/ssoi/n Geol. Sur.. vol. vi, 1894- p. 30. 
§Bi7//. Geol. Soc. Aineric.i.'.vol. vii, 1896, p. 3C>3. 
\\U S. Geol. Sur., Bull. 132. 1896, p 11. 
