The layers of solid clay in the Magothy ( ?) formation resemble those found in the Raritan 

 clay member but are not as thick or as extensively distributed as in the latter. 



In many places the upper part of the Magothy ( ?) formation is too fine in texture or too 

 clayey in composition to yield large quantities of water, but thin water-bearing zones, 4 or 5 

 feet thick, are found at various depths and yield satisfactory amounts of water for domestic 

 purposes. 



Magothy (?) formation — Kings County: Less than 10 wells penetrate the Magothy (?) 

 formation in the entire County and the limits and distribution of the formation are not clear. 

 However, the small amount of data available indicates that the Magothy beds probably do 

 not extend beyond an imaginary line, trending northeast-southwest roughly from Ridgewood 

 to Fort Hamilton. The absence of the formation in the northwestern part of Kings may be the 

 result of erosion, non-deposition or a combination of both. Within the franchise area of the 

 old Flatbush plant of the New York Water Service Corporation, the Magothy beds have been 

 almost entirely removed. Many of the present correlations indicate that glacial sands and clays 

 rest directly upon the Raritan formation in that area. As far as is known none of the wells in 

 Kings County that tap the Magothy are being operated at present. 



The elevation of the upper surface ranges from about 180 feet to 245 feet below sea level. 

 A maximum thickness of about 280 feet is attained in the southeastern part of the County. 



Magothy (?) formation — Queens County: About three-quarters of Queens County is 

 underlain by the Magothy ( ?) formation. In the northwestern part of the County where 

 bedrock and the Raritan formation lie at shallow depths, the Magothy is not present. As 

 shown on the accompanying contour map the most conspicuous topographic feature on the 

 Magothy surface in Queens County, is a deep valley extending from southern Queens toward 

 the northeastern part of the County. 



The formation is tapped by many wells in Queens that are used for air-conditioning and 

 public supply purposes. Most of these are situated in the southern and eastern part of the 

 County. From an elevation of about 15 feet above sea level in northeastern Queens the surface 

 of the Magothy drops to about 350 feet below sea level in the deep buried valley where it 

 passes beneath the barrier beach in southern Queens. In the County, the formation ranges in 

 thickness from about 30 to 400 feet. 



^ Magothy (?) formation — Nassau County: All of Nassau County is underlain by the 

 Magothy (?) formation except for a few small areas along the necks and bays on the north 

 shore, where glacial erosion has removed these beds. The most important of these are situated 

 at the northern tips of Great Neck and Manhasset Neck. In a few places along the north shore 

 the Magothy ( ?) crops out at the land surface, but in many instances the beds have been badly 

 disturbed by ice shove and show local arching and faulting of the beds. These outcrops have 

 been described and mapped by Fuller (15). 



A remnant of the original Cretaceous highland, often referred to as the "core of the 

 Island", is represented by the hilly area in east-central Nassau County where the Magothy 

 beds rise to at least 220 feet above sea level and are overlain by only a relatively thin mantle 

 of glacial deposits. The buried surface of the Magothy slopes gently to the south and north 

 from the highland area. Westward, it drops off rapidly to below sea level while to the east 

 of the highland area it slopes gently to the east and remains above sea level for some distance 

 into Suffolk County. Re-entrants in the surface of the Magothy along the north shore coincide 

 approximately with the southerly extensions of existing valleys along the north shore, and 

 suggest the former existence of larger and deeper embayments. Most of the north shore necks 

 or peninsulas are underlain by cores of the Magothy lying at relatively high elevations. Deep 

 buried valleys of the type and extent of those situated in Kings and Queens Counties do not 



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