the Al I doublet in order 58. In this plot, the spectra for the M6, M9 and L0 objects shown in Figures 1-3 are expanded and overlaid. Evidently, there is significant spectral structure in this part of the spectrum making it difficult to identify a true continuum level. All three spectral types show consistent features, in particular the wide depression containing the shorter wavelength Al I line. The equivalent width of the Al I lines clearly decreases from M6 to M9, but the change over these three spectral types is only about 25%. Because this region of spectrum is contaminated by 2o absorption, it is difficult to obtain accurate equivalent widths. A pseudo-equivalent width over a 4.2Å  interval centered on each line was obtained relative to the local continuum in the troughs where the Al I lines are found. For the stronger line of the pair at 1.3127 $\mu$m, the measured values of equivalent width for the M6 and M9 dwarfs respectively are 420$\pm$20 mÅ  and 300$\pm$40 mÅ. At L0, however, the pseudo-equivalent width of this line is $\le$40 mÅ. Clearly, at the transition from M9 to L0, both Al I lines vanish completely. Although only three objects bridging this 