276 J. S. Brown— Relation of Sea Water 



be suspected, and samples collected where the circum- 

 stances seemed to indicate such pollution were rejected. 

 A small assay kit was carried in the field for the purpose 

 of making approximate determinations of chloride, but 

 check samples were sent to the water laboratory of the 

 United States Geological Survey for analysis. The lab- 

 oratory analyses are given in this paper. 



Sketch of the Neiv Haven coast. — The New Haven coast 

 is a "drowned coast " and is consequently very irregular 

 in outline. There are large areas of flat tidal marshes 

 and in some places many small islands near the shore. 

 Portions of the coast have been cut away by waves, and 

 other portions have been built up. Spits and bar beaches 

 are common features. 



The bed rocks of the New Haven coast consist mainly 

 of gneiss and schist. At most places they are concealed 

 by glacial drift, which is generally not more than 30 to 

 40 feet in thickness, but portions of the coast are bare and 

 rocky, and small exposures of bedrock are common over 

 much of the region. The drift consists of till and strati- 

 fied drift. The till is generally variable in composition 

 and texture and is in places somewhat clayey. The strat- 

 ified drift has been re-worked by water and is usually 

 clean, well-bedded sand or gravel. It is confined mainly 

 to the valleys and certain low coastal plains of small 

 extent. Besides these formations there is a recent 

 deposit of black, slimy mud which covers the bottom of 

 New Haven Harbor and the tributary tidal estuaries and 

 whose thickness probably does not exceed 25 or 30 feet. 



Occurrence of ground water. — In the bedrocks ground 

 water is held mainly in open fractures, such as joints and 

 cleavage planes, and the water table is irregular. In the 

 stratified drift, which is very porous, the water table is 

 in general fairly smooth and stands but little above the 

 level of the sea or above adjacent streams. In the till, 

 owing to its varying porosity, the water table is irregular, 

 but usually water is found within a few feet of the 

 surface. 



Sea water in shallow wells. 



Most of the shallow wells on the New Haven coast 

 are either dug or driven and are less than 30 feet in depth. 

 More than half of them penetrate stratified drift. The 



