Could be an Alto-Cumuls Standing Lenticular... usually a mid-level cloud that forms over the tops of mountain ranges... caused by the uplifting of air on the upwind side and dissipation on the downwind side. As the name implies, it stands in one place and doesn't move, building, as stated on one side and dissipating on the other. The lenticular name is applied due to the lens shape of the cloud... thin on each end and thicker in the middle. For aviation, it is usually an indicator of turbulence... here in the western U.S. the turbulence can be quite severe over our western mountains...