Fragments of provincial Roman murals excavated at Munsingen, Kanton Berne and Holstein, Kanton Basel-Land (both in Switz.) were investigated. Much of the reported work was done by x-ray fluorescence and diffraction and by electron microprobe rather than electron microscopy. Egyptian blue was identified as a major constituent of samples from the blue pigmented layer and as a minor constituent with large amounts of alpha-Fe₂O₃ in samples from red areas. One electron micrograph made from a surface replica of a lightgreen mural fragment is shown. A ring electron diffraction pattern made in the same area reveals clay minerals oriented strictly perpendicular to the electron beam and more reliable evidence is shown by a single crystal pattern from a blue sample identified as CaCuSi₄O₁₀. 10 references. -- AATA