noun, plural su·per·stra·ta [soo-per-strey-tuh, -strat-uh, soo-per-strey-tuh, -strat-uh] /ˈsu pərˌstreɪ tə, -ˌstræt ə, ˌsu pərˈstreɪ tə, -ˈstræt ə/, su·per·stra·tums.
Examples from the Web for superstratum
After a time the superstratum of rock, which is full of cracks and seams, is undermined and precipitated into the chasm below.The Falls of Niagara and Other Famous Cataracts|George W. Holley
They are probably kept near to the surface of the earth by a superstratum of cold air.The Reason Why|Anonymous
Several pools, supplied by springs coming from under the superstratum of sandstone, were passed during the day.Journals of Australian Explorations|A C and F T Gregory