CONCLUSIONS

THE ISSUES

This lab module has investigated a specific geologic problem: How did the landforms of the New York City region originate? The problem was broken down into more detailed questions:

  • How did the long, narrow, parallel hills and valleys of Manhattan, the Bronx, and adjacent New Jersey originate?

  • How did the belt of randomly shaped hills and valleys of northern Brooklyn and Queens originate?

  • How did the gently sloping, flat plain of southern Brooklyn and Queens originate?

  • Large, isolated boulders are scattered across the landscape of all areas of the NY City region except the flat plain of southern Brooklyn and Queens. The bedrock from which they have been broken off lies many miles or tens of miles to the north or northwest. How did the boulders get to their present locations?

  • Why is the surface of the bedrock exposed in Manhattan, the Bronx, and adjacent New Jersey characterized by numerous parallel scratches and grooves?

This investigation of the origin of the landforms of the NYC region also was undertaken to address the more general question: What is the nature of 'proof' in geology? That is: How certain are geologists that their conclusions are correct? What does it mean in geology to 'prove' something?
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Geologists tend to favor a hypothesis that provides the answer to many related problems. A hypothesis that becomes generally accepted is called a 'theory'. Does the Glacial Theory satisfy this criterion in terms of how it explains the origin of landforms of the NYC region?
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WHAT YOU NEED TO BE ABLE TO DO ON THE LAB FINAL EXAM:

  1. For each of the following 5 questions:
    • Propose an answer in the form of one (or more) hypotheses.
    • Provide evidence that supports (or contradicts) each hypothesis.

    1. How did the parallel hills and valleys of Manhattan, the Bronx, and adjacent New Jersey originate?

    2. How did the belt of randomly shaped hills and valleys of northern Brooklyn and Queens originate?

    3. How did the gently sloping, flat plain of southern Brooklyn and Queens originate?

    4. How did the isolated boulders get to their present locations?

    5. What is the origin of the numerous parallel scratches and grooves on the bedrock?

  2. Answer the following two questions:
    1. Are geologic conclusions 'facts'? If not, what value do geologists' conclusions have? Explain your answer.

    2. Does the "Glacial Theory" merit the term 'theory'? Support your answer.

©2000
David J. Leveson