332 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1920. 



parts of the lithosphere, and these Appalachian oscillations in sea 

 level were by no means small affairs. Most of them are measured by 

 hundreds of feet and some by thousands. 



Excellent and very interesting oscillations occurred about those 

 more inland and very ancient positive areas known as the Cincinnati 

 and Nashville domes, the Ozark and Adirondack uplifts, and the 

 Wisconsin peninsula. Of the many formations that are found on 

 their flanks and which failed to pass over them much the greater 

 number are confined to one or the other side. The sequence of 

 formations on either side therefore differs greatly from that on the 

 opposite side. 



Much space is devoted in my Revision of the Paleozoic Systems to 

 a description of the inequalities in areal distribution of the forma- 

 tions that were laid down on the flanks of these epicontinental domes. 

 With a few corrections and modifications, in every case tending 

 to emphasize rather than to weaken the argument based on the 

 observed phenomena, the published statements concerning them in 

 that work have been further substantiated by more recent investi- 

 gations. Instead of overstating the number of oscillations in that 

 paper we can now prove many more instances than were known or 

 even suspected by me in 1910. 



In New York State alone the joint investigations carried on in 

 the Ordovician shales and limestones on the south and west sides of 

 the Adirondack mass by Doctor Euedemann and myself, and on the 

 Medina and Clinton formations with Mr. Hartnagle, have increased 

 the established cases of sea shifting implying more or less decided 

 differential vertical movements in the adjacent land masses to more 

 than twice the number contemplated when I wrote the Revision. 



Similarly the work of Mr. Charles Butts and myself on the 

 Mississippian formations in Illinois, Kentucky, Tennessee, and Ala- 

 bama has developed oscillations of like character that were scarcely 

 suspected six years ago. 



Very notable additions to our knowledge of Cambrian and Ozark- 

 ian oscillations also have been made in the course of my work on 

 the Paleozoic formations in Wisconsin. Before closing permit me 

 to give some details concerning at least one of many similar new 

 discoveries in this and adjoining States. 



Only a few years ago the stratigraphy of the Cambrian deposits 

 in the upper Mississippi Valley was practically unknown or at best 

 only very imperfectly understood. Because of certain misappre- 

 hensions, now clearly understood, the correlations of the several 

 sections by the State geologists of Wisconsin, Minnesota, and Iowa 

 were not only inadequate but quite in error. 



So long as the observed variations in character of deposits and 

 their fossil faunas were supposed to indicate nothing more than 



