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Professional Geologists Explore Iowa

page 7

 

 

The mid-19th century was a time of exciting theories and discoveries in science--including Darwin's On the Origin of Species, and Mendel's studies on heredity. In geology, Europeans and Americans were developing methods of relating time through rock units.

When the first investigations into Iowa's geologic history began there were few roads or settlements. Early geologist found swamps, thick forests, and endless prairie to challenge them. Traveling on horseback and by canoe they based their work on the rocks and fossils they observed and their studies of other locations. Their reports became official documents of the state and nation.

Nineteenth century geologists faced many physical hardships as they entered the new territory and state of Iowa.

 

"We have frequently...exhausted the last pound of eatables, and traveled a day or more without breaking our fast." We lost, by death, but one man, of cholera, at Muscatine, in Iowa, on July, 1849. Throughout the whole of that season, as cholera was very prevalent...we had great difficulties in inducing voyageurs to risk the exposure..."  -- David D. Owen  

 

David Dale Owen: In 1839, before Iowa was a state, Owen left his studies in the East and began to investigate the soils and mineral resources of the upper Mississippi River valley at the request of Congress. Here he found fossils and rocks that were familiar to those of his boyhood in Scotland and his earlier work in Indiana.

 

"The coal-measures of Iowa are shallow much more so than those of the Illinois coal field. They seem attenuated, as towards the margin of an ancient carboniferous sea: not averaging more than fifty fathoms in thickness." --David D. Owen.

 

 

James Hall:In 1855 the Iowa legislature appointed James Hall, former New York State Geologist, to conduct a geological survey. He published the two volume work in 1858.

 

"The lower geological formations, therefore, of this great northwestern plateau are the same as those known in New York and Pennsylvania, which form not only the undisturbed portion of that part of the country, but also the disturbed regions of the mountain ranges..." --James Hall

 

 

Charles A. White: The legislature again attempted to gather information about Iowa's mineral and agricultural wealth by directing the new State Geologist, Charles A. White, to crate a new survey and report in 1866. White's survey used the English system of rock unit nomenclature, which recognized the sequence and allowed for individual differences in rock units. Yet some of the earlier New York system names that Hall encouraged remained. He extended his work by calculating the thickness of Iowa rocks, above the Precambrian rocks, by relating the position and thickness of known outcrops.

 

White's geologic map of Iowa reflected new knowledge about the relationship of one rock bed overlying or hiding another. 

 

"All such rocks have received their stratified form by having been originally deposited as a precipitate or sediment in water, and with rare exceptions they have been deposited in the waters of the sea..." 

  -- Charles A. White

 

 

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