It is a clayey, calcareous, shelly, glauconitic (10-20 percent) silt. Its colors range from greenish-gray and gray-green to brownish-gray and light gray. It is rich in calcareous and siliceous microfossils. The matrix mineralogy shows a high calcite component, except in the lower part of the formation which is within a calcite dissolution interval. In the lower half of the formation quartz is predominant.
B18 Clay and Clay-Size Mineral Composition of the Cretaceous-Tertiary Section, Test Well Je32-04, Central Delaware
This study complements Delaware Geological Survey Bulletin No. 17 and deals exclusively with clays and clay-size minerals. The cored section at the location of Je32-04 has been subdivided into 25 clay zones on the basis of major changes in trends and degree of crystallinity of clay minerals. The composition of clay minerals varies from zone to zone. These clay minerals have been identified: kaolinite, berthierine, chlorite, illite, smectite, chlorite/smectite, illite/smectite, glauconite/smectite, and glauconite pellets. Other minerals present in the section include: zeolites (clinoptilolite-heulandite), gypsum, and elemental sulfur.
B2 Geology and Ground-Water Resources of the Newark Area, Delaware with a Section on the Surface Water Resources
This report describes the geological and lithological conditions in the Newark area, and the occurrence, quantity, and quality of the available ground-water supply. Newark is located on the Fall Line, the boundary between the rolling hills of the Piedmont on the north and the gentle slopes of the Coastal Plain on the south. Because the Piedmont is underlain by dense crystalline rocks and their weathered clayey soils, which are of low water-bearing capacity in contrast to the more permeable silts and sands of the Coastal Plain, the exploration for ground water was confined to the Coastal Plain south and southeast of Newark.