Febbuaby 11, 1910] 



SCIENCE 



219 



southern instance of satisfactory evidence of 

 glaciation in this country, so far as I recall; 

 but there are several records of glaciation 

 farther south than the point in the Sierra 

 Nevada referred to by them. Brief refer- 

 ences to these may be of interest. 



Science for November 22, 1901,' contained 

 a "Note on the Extinct Glaciers of New 

 Mexico and Arizona," by George H. Stone, in 

 which he reported evidences of glaciation in 

 one of the Eocky Mountain Eanges " as far 

 south in New Mexico as a point not far north 

 of Santa Fe" (latitude about 35° 41'). In a 

 later paragraph we read: 



The farthest south and west I have found traces 

 of extinct glaciers is at Prescott, Arizona. Around 

 Prescott are numerous moraines. The highest part 

 ol the n6v6 of this glacier could not have been 

 much above 9,000 feet. The central part of the 

 glacier is approximately in n. lat. 34° 30'. The 

 occurrence of an ancient glacier so far south as 

 this was probably due to a very great snowfall 

 owing to the proximity of the ocean. . . . Prob- 

 ably there were then small glaciers in some of the 

 cirques of northern exposure among the mountains 

 directly southeast of Prescott. 



E. D. Salisbury published an article on 

 " Glacial Work in the Western Mountains in 

 1901," in volume 9 of the Journal of Geology, 

 1901. Beginning with page Y28 is a brief de- 

 scription of glacial features in the moun- 

 tains near Santa Fe, between 35° 45' and 36° 

 north latitude. Some 50 cirques were found, 

 and about 80 ponds and lakelets. One of the 

 glaciers had a length of seven miles. Moraines, 

 stria3 and roehes moutonnees were observed. 

 In 1902 I had an opportunity to visit this 

 same region, and I entertain no doubt as to 

 the ample proof of local glaciation in those 

 mountains. 



In the Journal of Geology for 1905' is a 

 paper by Wallace W. Atwood on the " Glacia- 

 tion of San Francisco Mountain, Arizona." 

 This writer describes and figures terminal and 

 lateral moraines, and an outwash plain, and 

 reports the occurrence of striated boulders 

 and polished and grooved bedrock. I have 



= Vol. 14, p. 798. 

 = Vol. 13, p. 276. 



briefly mentioned evidences of glaciation on 

 this same peak, attributing a somewhat 

 greater amount of erosive work to the glacier 

 than is recognized by Atwood, and mentioning 

 what I then believed to be a terminal moraine 

 located near the mouth of a cirque.* The lati- 

 tude of San Francisco Mountain is about 

 35° 21' N. 



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 re- 

 ferred 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 northwest 

 slope, and I descended into the northwestern 

 part of the " crater." I 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 erosin, and that the encircling cliffs 

 were to be regarded as cirque-walls rather 

 than as crater-walls. The great central de- 

 pression 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 



* Technology Quarterly, Vol. 19, p. 410, 1906. 

 "Vol. 24, p. 116. 



