Sample spectra of MBM 40 used in this study. Top panel: single GALFA spectrum at α = 242.7583° ,δ = +21.8084° (J2000.0), in the lower part of the western ridge of MBM 40. Bottom panel: sample FCRAO ¹²CO spectrum near the same position as the H I, obtained by averaging 64 spectra in an 8 × 8 pattern to enhance the S/N. The vertical dashed line shared by two plots indicates the bulk velocity of the cloud (3.35 km s⁻¹). The H I spectrum shows the brightness temperature (T_B), and the ¹²CO spectrum is in terms of the radiation temperature (T_R).