ABSTRACT 



The wash-bore method of soil sampling, which can be employed from 

 both floating and land equipment, was found to be an excellent technique 

 for subsurface study. Seismic refraction is a valuable tool in the 

 coastal environment but phenomena to be considered when interpreting 

 records include a) "the blind zone," b) the non-zero time intercept, 

 c) time gaps in the time-distance plots over buried peat, and d) vari- 

 able thicknesses of dry sand layers. 



The seismic method successfully located Pleistocene and bedrock 

 topography. Dry sand, water-saturated sandy sediments, glacial till, 

 and bedrock provide well-defined seismic contrasts. Glaciomarine clay 

 does not show a seismic contrast with respect to sandy, water-saturated 

 sediments. 



Topography exposed during lower sea level 10,000 to 11,000 B.P. 

 (Kaye and Barghoom, 1964) has a dominant influence on modem coastal 

 geology. Barrier-island features became anchored on drumlins and other 

 Pleistocene features as the relative sea level rose. Thick sequences of 

 sediments, including clam-flat facies, channel deposits, and point-bar 

 deposits, accumulated in the estuaries behind these barrier beaches. 

 Major channels of the estuaries migrated landward with the sea-level 

 rise, a hypothesis in agreement with McCormick (1968). 



A bedrock high beneath the centerline of the barrier beaches on 

 all seismic profiles is perpendicular to barrier elongation. Bedrock 

 topography is extremely irregular and drops over 150 feet beneath the 

 Parker and Essex estuaries. Essex Bay appears to move in deep channels 

 incised in underlying bedrock; two mid-estuarine sand bodies, Essex 

 flood-tidal delta and Middle Ground, appear to have rather stable 

 sedimentary deposits. 



Although no radiometric dates were determined for samples taken 

 in this study, the sedimentary stratigraphy fits the time frame of 

 Mclntire and Morgan (1963) and Kaye and Barghoom (1964) . 



FOREWORD 



CERC is publishing this report because of its interest and value to 

 coastal engineers. 



This report was prepared by Eugene G. Rhodes under Contract No. DACW- 

 72-70-C-0029 with CERC. It is an edited version of a thesis submitted in 

 partial fulfillment for a M.S. Degree in Geology at the University of 

 Massachusetts. 



Special appreciation is extended to Miles 0. Hayes, who served as the 

 immediate supervisor of the study from inception to completion. Profes- 

 sors Joseph H. Hartshorn and Randolph W. Bromery provided a constructive. 



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