The process generated by the crossings of a fixed level, u, by the process Pn (t) is considered, where
and the Xi (t) are identical, independent, separable, stationary, zero mean, Gaussian processes. A simple formula is obtained for the expected number of upcrossings in a given time interval, sufficient conditions are given for the upcrossings process to tend to a Poisson process as u→∞, and it is shown that under suitable scaling the distribution of the length of an excursion of Pn (t) above u tends to a Rayleigh distribution as u→ ∞.