WATER 



table: 



EXPLANATION 



STRATIFIED DRIFT 



Till 



SAND AND GRAVEL 





SAND. SILT AND CLAY 



SAND 



>2 



HETEROGENEOUS COMPACT CRYSTALLINE BEDROCK 



MIXTURE or SAND. GRAVEL. 

 SILT AND CLAY SIZED 

 MATERIAL 



Figure 14. Block diagram illustrating the general geologic features of a 

 ground-water reservoir on the north shore of Long Island Sound. Adapted 

 from Cervione and others (1972, Fig. 32). 



The ground-water reservoirs contain at least two and generally 

 three major hydrogeologic units whose properties affect the storage and 

 movement of water. Maps showing the known extent, thickness and hydraulic 

 properties of the most important unit, stratified drift are available for 

 parts of Subregions 1, 4 and 5 in the references cited in the introduction 

 to this section. The important characteristics of all three hydrogeologic 

 units is summarized on Table 5. 



33 



