Description: <DIV STYLE="text-align:Left;"><DIV><DIV><P><SPAN>This vector data set contains the rock unit polygons for the 1:24,000-scale statewide surficial geology. This layer was created by merging 1:24,000-scale rock unit polygons from Delaware Geological Survey (DGS) published surficial geologic maps. This surficial geology layer represents the "current thinking" of the DGS and may be different from original geologic interpretations portrayed on the published maps.</SPAN></P></DIV></DIV></DIV>
Description: <DIV STYLE="text-align:Left;font-size:12pt"><DIV><DIV><P><SPAN>This vector data set contains the rock unit polygons for the 1:24,000-scale statewide surficial geology. This layer was created by merging 1:24,000-scale rock unit polygons from Delaware Geological Survey (DGS) published surficial geologic maps. This surficial geology layer represents the "current thinking" of the DGS and may be different from original geologic interpretations portrayed on the published maps.</SPAN></P></DIV></DIV></DIV>
Description: <DIV STYLE="text-align:Left;"><DIV><DIV><P><SPAN>The vector data set contains the rock unit polygons for Open File Report No. 54. The Piedmont rock units from Delaware Geological Survey Geologic Map No. 10 were revised in 2021 based on new rock geochemistry, geochronometric data, petrography, and recent detailed mapping. Major revisions include revising the extent of the Christianstead Gneiss and Windy Hills Gneiss; abandoning the Wissahickon Formation as originally mapped in Delaware by Bascom (1902, 1905) and Bascom et al. (1909, 1920, and 1932) and replacing it with the Mt. Cuba Gneiss, a lithodeme of the West Grove Metamorphic Suite (Bosbyshell et al., 2012, 2013, 2014, 2015), and reserving the Wissahickon Schist/Formation for the metasediments on the east side of the Wilmington Complex magmatic arc and referring to them herein as Wissahickon Formation (restricted sense); extending the Rosemont Shear Zone from Pennsylvania southwest through Delaware to Maryland separating the Mt. Cuba Gneiss and the Wilmington Complex; formally naming and describing two new units in the Wilmington Complex - the Greenville Gabbro and the Thompsons Bridge Gneiss.</SPAN></P><P><SPAN /></P></DIV></DIV></DIV>
Copyright Text: Digital Geology Layer for DGS Open File Report No. 54 (Bedrock Geologic Map of the Delaware Piedmont)