3-04. SUBSURFACE SOIL AND ROCK CONDITIONS 



The subsurface explorations indicate the following general soil 

 and rock sequence in order of increasing depth from ground 

 surface: 



o Miscellaneous Fill 



o Organic Silt and Peat 



o Marine Sands 



o Glacial Till 



o Bedrock (assumed) 



Due to the complex environments responsible for the creation of 

 these deposits, all strata may not be present at specific site 

 locations. These strata are discussed below in order of 

 deposition. 



Bedrock 



Bedrock was not encountered in any of the test borings. 

 However, available geologic maps indicate the site is underlain 

 by Cambridge Argillite (29) . 



Glacial Till 



During the Pleistocene glacial period, a very dense 

 non-stratified, unsorted material known as glacial till was 

 deposited over the bedrock surface in the project area. The 

 glacial till encountered at the site is typically a very dense, 

 silty fine SAND to sandy SILT, with trace to some gravel, 

 containing occasional cobbles and boulders. Glacial till soils 

 were encountered at depths of 15 to 30 ft. below ground 

 surface. Thickness of this strata was not determined since 

 none of the test borings penetrated this layer completely. 



Marine Sand 



As a result of the fluctuating harbor levels, a layer of silty 

 medium to fine SAND was found to overlie the glacial till 

 deposits. Where encountered, this stratum ranged in thickness 

 to up to 9.0 ft. 



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