Figure 43 . — Sealing of an opening into the North Alley Burrow with vegetction. During the night of May 16 , 1948 , the roof 
of a nest cavity partially collapsed. The hole was not large enough to permit the passage of a rat. During the night the 
rats cut and placed the goldenrod leaves shown just above marker No. 11. The pine needles shown above and to the 
right contain those shown in figure 36 . 
43 
