11 
*• 
spectacular slumping of the .s, uth side of the cone on March 17 
one! the re-issuing of* lava from the Ahufo area, the only activity 
seen, for months on Mesa tie las Hornitos had been the grtcusltf 
forming of a hogback ridge rising up to 15 meters above the 
surrounding cold lava field. In one week the new flow had reached 
the i*ese of the hills southwest of ‘.he outer limits of the earlier 
flows. The broad front sent lobes to the northwest and southeast 
along the margin of the laf& field. 
During the first two weeks in September only the s , uthernmost 
one of the four lobes in the vicinity of the Upper C&sifca remained 
active. This lobe was fed by a stream about 5 meters wide that 
«• 
originated near the base of a fumarole-to pea hill between the 
Upper Cess its* and the volcano, and It followed the south and vest 
base -of Jar/itiro hill. From the same source a newer, smaller 
lobe was seen on September 16 to be riding slowly over old leva 
a few hundred meters east of the Upper Caslta. 
the 
A temporary resurgence of the lav 
flow of July 12 to August 7 was on 
b 
near the east end of 
ept ember 18 sending out 
two -hart narrow lobes over old. lava. 
toward the remaining uncover 
ed part of a peninsula of virgin land. The boca of the flow south 
from Ahu&n, which had coamenceu on August 8, had migrated by 
September 18 about 50 meters south, and its still-moving front 
had advanced to a point approximately due oufch of the eastern- 
most edge of the b&se of the cone. 
Figure 4 shows the Par lout in lavas from March 17 to Angus 
3L> 1946; it does not include the September I lows described above. 
