THE HYPOTHESIS: One or more of the major landforms of the NY City Area formed due to the more rapid wearing away of areas underlain by non-resistant materials and less rapid wearing away of areas underlain by resistant materials. THE PREDICTION: One or more areas that have higher elevations should be found to be underlain by more resistant material than adjacent areas with lower elevations. EVALUATING THE PREDICTION: Elevation data may now be compared to the Erosion Resistance Index to evaluate the prediction. If the prediction is fulfilled, how would you expect the Erosion Resistance Index to vary with elevation? If it is not fulfilled, how would you expect the Erosion Resistance Index to vary with elevation? If the prediction is fulfilled, the E.R. Index should vary with elevation as follows: If the prediction is not fulfilled, the E.R. Index should vary with elevation as follows:

What you need to do:

Click on the pink button and print out the 'Resistance-Elevation Tabulation Table - Brooklyn/Queens' (printout # H-3). Next, in the spaces provided in the Resistance-Elevation Tabulation Table, tabulate the following information for each measuring station (one station has been done for you as an example): Material type, either B, U, S or L (from the Surficial Geologic Map, printout # M-4) Erosion-Resistance (E-R) Index (from the E-R Index Calculation Table, printout # Q-6). NOTE: Use the L.I. Hill Sediment index for material U; use the index for L.I. Plain Sediment for materials S or L. Elevation (from the Topographic Map, printout # G-4) Now that the data has been assembled, it can be used to see if adjacent high and low areas are underlain, respectively, by materials of high and low resistance to erosion. Determine the highest and lowest Erosion Resistance (E-R) indices and enter them in the indicated spaces under the table. Determine the range of E-R Indices by subtracting the lowest from the highest index. Enter the result in the indicated space. Determine the highest and lowest elevations and enter them in the indicated spaces. Determine the range of elevations by subtracting the lowest from the highest elevation. Enter the result in the indicated space. How well do the E-R Indices and the elevations correlate? (Does the E-R Index rise and fall as the elevation rises and falls?) Enter your conclusion in the indicated box. Is the prediction largely fulfilled? Partly fulfilled? Minimally fulfilled? Unfulfilled? Enter your conclusion in the indicated box. Answer the questions found in the textbox below: For Brooklyn and Queens, how well is the prediction fulfilled? What is it about the material under Brooklyn and Queens that results in the degree of correlation between E-R indices and elevation that you have described?

# H-3

©2003
David J. Leveson