The coherence between vertical temperature profiles separated in time is studied. Time lags from 12 min to 19 hours and vertical wavelengths from 2 to 300 m are considered. The wavelengths shorter than 10 m show no significant coherence even for 12-min separations. The longer wavelength bands exhibit coherence time series with significant structure out to the largest lag measured. For the wavelength band between about 21 and 42 m the results are directly interpretable as vertical modes. In the other wavelength bands considered, there is evidence that the perturbations are propagating. The coherence and phase time series are compared with the Garrett and Munk internal wave model.