A Cretaceous Sponge Small 171×320 Medium 341×640 Large 546×1024 Download Tiff Original 1280×2400 | (746.3 KB) Description A Cretaceous sponge with silicious skeleton retaining its form. (Ventriculites simplex). Keywords cretaceous, Silica, sponge Galleries Sponges Source: Amadeus W. Grabau A Textbook of Geology (Boston: D.C. Heath & Co., 1920) 326
