1894. ] NEW YORK ACADEMY OF SCIENCES. 149 
lowing day the journey was resumed in another stage that 
brought us to Guerrero, at the foot of the mountains. Here be- 
gan a journey of about 100 miles on mule back. The ride takes 
about three days. After climbing innumerable hills, we at last 
came to the highest ridge, called the Cumbre of Jesus Maria, and 
descended a steep canon to the town. 
The following day we set out for the falls. The trail wound 
over a high range of hills, whose vertical cliffs form one side of 
the canon of Jesus Maria. <A long circuitous path led up to the 
top of the cliffs, beyond which easier slopes rose much higher. 
Before reaching the stream above the falls, the trail crosses a 
gorge several hundred feet deep, with nearly vertical sides. 
Climbing the intervening hill, we came to the Bassasseachic 
River above the fall. 
My visit being in the dry season, the bed of the river seemed 
dry, but on reaching the bottom of the ravine the water was 
found flowing in tortuous channels, 10 to 20 feet deep, worn in 
the bare rock by the passage of sand. In some places the rock 
was pitted as though by the removal of phenocry sts, leaving a 
cellular ground mass. Other parts of the ravine seemed to be 
silicious limestone; near the crest of the fall the rock is proba- 
bly porphyry, but there are no sharp dividing lines as one shades 
into the other insensibly. 
The bed of exposed rock covered by flood in the rainy season 
is 50 to 100 feet wide. The cutting action of sand and gravel is 
also illustrated, just above the fall, for at this point there is a 
natural arch of rock formed by the destruction of a pot-hole, 
under which the water passes before taking its final leap. There 
are several pot-holes, 3 to 5 feet in diameter and 10 to 20 feet 
deep, near the deep channel, in which the water is now flowing. 
It is not until actually at the crest of the fall that the visitor 
realizes that there is any break in the bed of the river. Only by 
leaning over the precipice and looking down nearly 900 feet, can 
the bottom be seen, or even the water after it leaves the edge. 
The amphitheatre below the falls is surrounded by vertical 
cliffs that rise 800 to perhaps 2,000 feet above the bed of the 
stream. From the fall to the cliff opposite is about 3,000 feet, 
and the extreme width of the canon is about 1,500 feet. On the 
bottom there are piles of debris fallen from above, and over all 
is a dense forest of pine and cedar. The canon turns to the 
right, and a further view is shut off by the high cliffs beyond. 
On looking down from the edge of the fall the task of getting 
to the bottom seems an impossible one. But there is a trail on 
the left that is hidden by a knifelike spur of rock that forms part 
of one side of the canon, so we have to go back a few hundred 
