a gasket or seal member constructed of elastomeric material has at least one slot extending lengthwise of the member and across its thickness at an oblique angle to the sealing faces . there may be a plurality of slots spaced apart across the width of the member . in a preferred form of the invention multiple , parallel slots are formed at an oblique angle to the seal faces of the member forming branchiate - like layers of gasket material , in which each of the layers partially overlays at least one other layer .