Distribution of the cold, dominantly molecular, gaseous phase of IVC135+54. Using Eq. (9), we convert the FIR excess emission (Figs. 7 and 8) into upper limits to the molecular column density. The blue rectangle indicates the region in which Weiß et al. (1999) have detected ¹²CO and ¹³CO. Superposed are the HVC contours, starting at 6 × 10¹⁹ cm^-2 and increasing in steps of 2 × 10¹⁹ cm^-2 (red) and the IVC contours starting at 1.1 × 10²⁰ cm^-2 and increasing in steps of 4 × 10¹⁹ cm^-2 (black).