Query: What was uplifted from extreme compressive stresses and pressure? 
Context: Under extreme compressive stresses and pressure, marine sedimentary rocks were uplifted, creating characteristic recumbent folds, or nappes, and thrust faults. As the rising peaks underwent erosion, a layer of marine flysch sediments was deposited in the foreland basin, and the sediments became involved in younger nappes (folds) as the orogeny progressed.