Notices of Memoirs—Glaciation in the United States. 281 
F. J. H. Merrill reports in Science for July, 1906,* ‘‘ Evidences of 
Glaciation in Southern Arizona and Northern Sonora.” In the vicinity 
of Nogales, and elsewhere, were found deposits which he believed to 
be of glacial origin, while the surface had “the rolling topography 
and pitted surface of a moraine’’. Nogales is in latitude 31° 20’ N. 
The above references may be but a partial list of the published 
reports of glaciation south of the point in the Sierra Nevada referred 
to by Fairbanks and Carey; I have made no effort to prepare 
a complete list. Of these reports, the one on glaciation near Nogales 
is the most striking, because of the low latitude and low altitude 
in which the deposits are found. The evidence as reported does not 
appear sufficiently convincing, in view of the strong probabilities 
against the occurrence of glacial deposits in the region in question. 
Merrill’s descriptions suggest a landslide origin for the deposits which 
he took to be glacial. With reference to the glaciation of San 
Francisco Mountain I wish to add the following paragraphs. 
On my visit to San Francisco Mountain I ascended the volcano by 
the north-west slope, and I descended into the north-western part of 
the ‘crater’. JI was impressed with the cirque-like form of the 
depression, and came to the conclusion that the original crater had 
been destroyed by stream and glacial erosion, and that the encircling 
cliffs were to be regarded as cirque-walls rather than as crater-walls. 
The great central depression of the volcano consisted of several more 
or less distinct cirques uniting down-stream. Near the mouth of one 
of these was what I interpreted as a crescentic terminal moraine, 
rising 150 feet or more above the valley floor. But there were 
certain associated features which puzzled me at the time. Up-stream 
from the supposed moraine the floor of the cirque appeared to be 
deeply buried by an accumulation of rock débris which was generally 
as high as, and near the head of the cirque distinctly higher than, 
the morainal ridge. This débris was in places, especially near the 
marginal walls arranged in parallel ridges trending with the axis of 
the valley; and in the depressions between the ridges were patches of 
snow and some small ponds. Thus the moraine had a steep frontal 
slope, but at the back merged with the ridged rock débris, which rose 
to still higher levels. There were some depressions in the rock débris, 
25 to 40 feet deep, which I took to be ice-block holes. No bedrock 
was seen in the cirque floor. 
During the recent meeting of the Geological Society of America, 
Professor H. B. Patton, of Boulder, Colorado, exhibited some photo- 
graphs of the rock streams of Veta Mountain, Colorado. One of these 
photographs showed the high and steep front terminus of a rock 
stream, and resembled very closely the front slope of the supposed 
moraine in the San Francisco cirque. Others of his pictures showed 
the longitudinal parallel ridges which characterize some rock streams, 
with bands of snow lying in the hollows between the ridges, just as 
was the case in the San Francisco cirque at the time of my visit. 
If the concentric wave-like ridges pictured by Howe? were present 
in the San Francisco deposits, I did not notice them. 
Pviol-sxiv, p. 116. 
* «* Landslides of the San Juan Mountains ’’: U.S.G.S. Professional Paper, No.67. 
