REPORT ON THE PANAMA CANAL 
199 
divide to the east. It is estimated that the Cucaracha Slide drains an 
area of 80 acres. The slide is sharply limited on the north by the break 
in Gold Hill already mentioned, which extends approximately at right 
angles to the Canal; its southern Hmit is not so well defined. 
The limit of the East Culebra Slide is sharply marked on the south 
by the break through the north part of Gold Hill which runs approxi- 
mately at right angles to the Canal. The Northern boundary is not so 
sharply marked. The sHde extends sKghtly beyond the subordinate 
divide on the east, so that east of the slide the drainage is away from the 
Canal. 
The West Culebra Slide is limited on the south by breaks beginning 
at the Canal some distance north of Contractors Hill; on the west by 
breaks which are sharply defined in Zion Hill; and less sharply in Culebra 
Hill. In the narrow valleys between Culebra and Zion Hills and be- 
tween Zion and Contractors Hills the break extends beyond the divide, 
and the drainage is to the west. 
Possible Extensions of the Great Slides. — The very important question 
now arises: Will the great slides extend their limits and cause further 
serious trouble? 
In general, the Committee beHeves that no great extension of these 
slides is probable, because the soft rock constituting a very large part 
of the slides is quite limited in extent, except east of the East Culebra 
Slide, and conditions elsewhere are unfavorable for extensions. 
The Cucaracha SKde cannot greatly extend its area on account of 
the basaltic intrusions which surround it; but its eastern and southern 
limiting banks are still breaking down, and the movement of the slide 
may be revived to a small degree. Plugs or branches of intrusive basalt 
standing as obstructions across the former course of the slide restrain 
its movement; but the strength of these obstructions cannot be deter- 
mined from present exposures. 
The West Culebra SHde is pretty definitely Hmited on the west by 
the hard rocks of Culebra and Zion Hills; but between the active part 
of the slide and Contractors Hill there is a considerable mass of the 
Cucaracha formation, which seems never to have taken part in the 
slides. The effect on this mass of the settUng of the adjacent moving 
material cannot certainly be predicted. Indeed it is not impossible 
that a considerable part of it may finally be set in motion; but the 
mass involved will be small in comparison with the active West 
Culebra SHde. 
East of East Culebra SHde the soft formation continues, but the 
slope is gently away from the Canal. Additions to the slide to the east 
