A nonwoven lap of very fine continuous filaments, crimped or not, obtained by means of a controlled direct spinning process, with a weight between 5 g/m.sup.2 and 600 g/m.sup.2, and formed, after napping, of composite filaments separable in the direction of their length, characterized in that said composite filaments have a filament number between 0.3 dTex and 10 dTex and are formed, each, of at least three elementary filaments of at least two different materials and comprising between them at least one plane of separation or cleavage, each elementary filament having a filament number between 0.005 dTex and 2 dTex, the ratio between the cross-sectional area of each elementary filament and the total cross-sectional area of the unitary filament being between 0.5% and 90%.