274 The American Geologist. October, i>s93 
one before and the other after the depression which is record- 
ed by the loess. 
Prof. J. W. Si'kmki; docs not accept the doctrine of the 
general permanence of the continents, nor that the earth's 
contraction is the cause of its epeirogenic movements. The 
late Tertiary or Quaternary deep subsidence of the West In- 
dies shown by submarine valleys, and great uplifts elsewhere 
during the Pleistocene period, as learned by Russell for the 
St. Elias range, must be taken into account in the restora- 
tions of former coast lines. 
The presiding officers for the Saturday session, major J. 
W. Powell and Dr. O. A. Derby, being absent, their places 
were occupied by Prof. Dr. Groth, of Munich, and Prof. 
James Hall. This session was devoted to papers on the 
glacial drift and history of the Ice age, of which a report is 
separately presented in the preceding pages. 
At its close the congress voted its thanks to Dr. Josua 
Lindahl, Profs. Chamberlin and Salisbury, Mrs. Louise F. 
Lowery, and other members of the local committees whose ef- 
ficient work led to this important gathering of geologists and 
geological papers. 
Missouri now Furnishes Two-thirds of the Zinc Mined 
in the United States, and Jasper county supplies most of it. 
Missouri is also second in the production of lead. Lead and 
zinc occur in quantity in one-fourth of the state. Lead and 
zinc are now mined in about 21 counties, and have been 
mined in 31, and been found in 40 counties, and the production 
of Jasper county alone reaches over $75,000 a week. Iron has 
been mined in 14 counties, and occurs quite abundantly in 
26 counties. Coal is or has been mined in 47 counties of the 
state, and may be found under an area of 23,100 square miles. 
This fact is ascertained by geological examinations. Over 50 
counties contain valuable ore deposits or else good quarries of 
building stone. 
Over one-third of the state owes its prosperity to mining 
operations. The first two State Geological Surveys defined 
the boundary and area of the coal fields. A preliminary re- 
port of Bates county was published in 1874. It was repub- 
lished and widely circulated; the result was the building of 
railroads and development of coal mines, and the growth of 
the mining town of Rich Hill. Black slate generally overlies 
coal beds, but there are also black slates of older age. Pre- 
vious to the establishment of the Ohio Geological Survey, 
enough money had been spent in profitless searching for coal 
on those black slates to pay for the Geological Survey. So it 
has been in New York and elsewhere — and in Missouri. I have 
found where such slates had been shafted through in search- 
ing for coal to no profit. G. 0. BUOADHEAI). 
