Englishtown Formation

GM27 Geologic Map of the Elkton, Saint Georges, and Delaware City Quadrangles, Delaware

Geologic mapping was conducted at 1:12,000 with a 1-ft contour basemap. In some instances, stratigraphic boundaries drawn at topographic breaks reflect detailed mapping using LiDAR data. Elevations of stratigraphic contacts along stream valleys are projected from subsurface data. Except for a few erosional bluffs, these contacts are covered by colluvium. This map supersedes this portion of Geology of the Chesapeake and Delaware Canal Area, Delaware: Delaware Geological Survey Geologic Map Series No.

GM26 Geologic Map of the Cecilton and Middletown Quadrangles, Delaware

Mapping was conducted using field maps at a scale of 1:12,000 with 2-ft contours. Stratigraphic boundaries drawn at topographic breaks reflect detailed mapping using contours not shown on this map. Most stratigraphic units mapped in stream valleys are projected from subsurface data. Except for a few erosional bluffs, these units are covered by colluvium. This map supersedes Geology of the Middletown-Odessa Area, Delaware: Delaware Geological Survey Geologic Map Series No. 2 (Pickett and Spoljaric, 1971).

RI78 Subsurface Geology of the Area Between Wrangle Hill and Delaware City, Delaware

The geology and hydrology of the area between Wrangle Hill and Delaware City, Delaware, have been the focus of numerous studies since the 1950s because of the importance of the local groundwater supply and the potential environmental impact of industrial activity. In this report, 490 boreholes from six decades of drilling provide dense coverage, allowing detailed characterization of the subsurface geologic framework that controls groundwater occurrence and flow.

Englishtown Formation

Light-gray to white, micaceous, slightly silty to silty, fine-grained, slightly glauconitic quartz sand. In outcrop, it is extensively burrowed with Ophiomorpha burrows. Ranges from 20 to 50 ft in thickness. On the cross-section, the Englishtown is shown only where the sands are well developed. Interpreted to be nearshore marine to tidal flat in origin.

OFR24 Saturated Thickness of the Water-Table Aquifer in Southern New Castle County, Delaware

This map shows the saturated thickness of the water-table aquifer. This aquifer consists of the deposits of the Columbia Formation and those portions of the Magothy and Englishtown-Mt. Laurel formations, and Rancocas Group that are hydraulically connected with the Columbia deposits (see Groot, Demicco, and Cherry, 1983). For example, large, saturated thicknesses in the zone trending northeast-southwest near Townsend reflect the addition of the sands of the Rancocas Group to the total thickness of the sands of the overlying Columbia Formation.

OFR21 A Guide to Fossil Sharks, Skates, and Rays from the Chesapeake and Delaware Canal Area, Delaware

In recent years there has been a renewed interest by both amateur and professional paleontologists in the rich upper Cretaceous exposures along the Chesapeake and Delaware Canal, Delaware (Fig. 1). Large quantities of fossil material, mostly clams, oysters, and snails have been collected as a result of this activity. Recent dredging (1978, 1981) by the United States Army Corps of Engineers has helped expose a rich vertebrate fossil assemblage. It includes representatives from the classes Reptilia, Osteichthyes, and Chondrichthyes.

OFR5 Removal of Metallic Contaminants from Industrial Waste Waters by the Use of Greensands, A Preliminary Report

The Delaware Geological Survey, in cooperation with the U. S. Bureau of Mines, has investigated glauconite-bearing greensand deposits in Delaware for several years. The purpose of this effort is to find possible practical uses for this potentially important mineral resource. This report briefly describes the preliminary results of one phase of the study: application of greensands to the purification of industrial waste waters.