Geologic image in the Kentucky Geological Survey data repository.Image Name: Image Date: 9/20/2008 Category: photo_outcrop Source: Carey, Dan Format: JPG Size (MB): 1.40 Pixel Dimensions: 2816 x 1584 Description: Mountain Parkway, mile 75.0: Close up, limestone concretion in Hyden Formation (Ph). The concretions formed in the clay depositions that became shale of the Hyden Formation. The concretions' spherical forms are compressed into ellipsoidal disc shapes by the pressure of subsequent overlying deposits.