In Kings county, particularly, the Jameco was once a good aquifer but now has largely 

 been salted by overpumping and perhaps also by lack of recharge from rainfall. This area is 

 paved and sewered in such manner that a large percentage of the rainfall is carried at once 

 to salt water. 



GARDINERS CLAY 



This formation is said to have been laid down in lagoons similar to Jamaica, Great South 

 and other bays now existing almost continuously along the south shore of the island. It is apt 

 to be dark in color, contains much organic matter and is rich in fossils. Shells found in it appear 

 to be those of oysters, clams, mussels, scallops, etc., the same or very similar to those now 

 existing in the present lagoon. Unfortunately, the geologists find it difficult to identify this 

 clay in well logs and the real extent of it has not been determined. 



The type locality from which this stratum was named is Gardiners island where it out- 

 crops but where it has been much distorted by ice shove so that the strata are vertical instead 

 of horizontal. It is best known in the area under Brooklyn and in that neighborhood where 

 the Gardiners lies on the Jameco aquifer and under the upper glacial deposits. 



These two deposits were correlated as being the same, and it was assumed from reasoning 

 by analogy and from the present conditions that the two were more or less connected along 

 the south shore of the island. Fuller (15) noted clay outcrops in the north shore bluffs which 

 he believed to be the same formation, but for a period the geologists abandoned the idea that 

 this stratum was continuous. Borings at Brookhaven Laboratory showed Gardiners and led to 

 reconsideration of the correlations which are now held to show Gardiners in a number of 

 scattered locations. It is now assumed to be nearly continuous for the whole length of the 

 south shore resting on Magothy and not rising above Elevation -60, but the information with 

 regard to it is insufficient to justify attempting to draw contours on it. 



Under Brooklyn the Gardiners surface more or less parallels thai of Jameco much as 

 though the former were a blanket spread over the latter formation and generally extends out- 

 side of it for some distance. This gives considerable slope to the surface. Still reasoning from 

 analogy and present conditions, it is improbable that this formation was deposited in a lagoon 

 of fixed location. So to assume would require a confining bar beach of unusual height and the 

 deposit of the clay in relatively deep water. 



As it is believed to be an interglacial formation, it must first have been laid down during 

 a period when the melting ice sheet was replenishing the ocean and sea level was rising. It is, 

 therefore, suggested that the original lagoons were formed on the Continental Shelf farther 

 south and at a materially lower elevation than the present northerly limit of this stratum. As 

 sea level rose, the bar beach was forced in a northerly direction over the clay deposited in the 

 original lagoon and the lagoon itself was kept moving inward and upwards until the next 

 advance of an ice sheet caused recession of sea water. This would give a sloping formation 

 terminating in a flat top and the sloping portion would be covered by beach and dune sand. 

 The top would not be covered but left as a level swampy area until eroded by the outwash of 

 the advancing ice and eventually buried by glacial drift (GW-2, Fig. 6). 



It is regrettable that the northerly limit of this clay in the western part of the island 

 lies in a well-less region under the Harbor Hill moraine and can be only guessed at. 



Under Brooklyn this formation is highly important hydrologically. Farther east its 

 importance cannot be determined until more is known of its location and characteristics. It 

 is probable, however, that over a broad belt along the south shore it provides a more or less 

 impervious barrier between the Upper Glacial and Magothy, a condition which might have 



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