798 



SCIENCE. 



[N. S. Vol. XIV. No. 360. 



' Note on the Extinct Glaciers of New 

 Mexico and Arizona ' : Geo. H. Stone. 



In southwestern Colorado there were once 

 extensive glaciers on the La Plata and San 

 Juan mountains. The largest of these was 

 70 miles long and filled the valley of 

 the Las Animas river. It deposited a 

 terminal moraine just north of Durango, 

 Colo., but appears not to have reached 

 so far south as the 37th parallel of latitude. 

 In New Mexico east of the Eio Grande the 

 only extinct glaciers that I have been able 

 to trace were along the high range that 

 forms the southern extension of the Sangre 

 de Christo range of Colorado. Each lateral 

 valley of this range contained its glacier 

 both in Colorado and as far south in New 

 Mexico as a point not far north of Santa 

 Fe. In the region south of the Galisteo 

 are the Ortiz, San Pedro, San Dias, Peder- 

 nal, Gallina and Jicarilla mountains. I 

 have visited all these mountains and found 

 no proof of the former existence of glaciers. 

 South of White Oaks is a lofty north and 

 south range — the Sierra Blanca. It is the 

 highest range in that part of New Mexico, 

 probably rising to near 11,000. It is a 

 place of great snowfall, as its name signi- 

 fies. In valleys of northern exposure I 

 f )und large masses of snow late in June. 

 I was not able to find moraines. ' West of 

 the Rio Grande the main southeast spur 

 of the San Juan mountains passes into New 

 Mexico as the Conejos range. This range 

 falls rapidly toward the south and was 

 glaciated for not more than 30 to 50 miles 

 south of the Colorado-New Mexico line. 

 South of this there are no mountains in 

 western New Mexico so high that we could 

 expect to find traces of glaciers on them 

 until we reach the lofty Mogollons. They 

 have a heavy snowfall. They are rather 

 inaccessible and I have not visited them. 

 I have explored the higher mountain 

 ranges that lie south of the Gila river in 

 New Mexico and Arizona, but no moraine 



or other sign of a glacier was I able to find. 

 The farthest south and west I have found 

 traces of extinct glaciers is at Prescott, 

 Arizona. Around Prescott are numerous 

 moraines. The highest part of the n^ve 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. It is doubtful if there was 

 any mountain range high enough to have 

 had its glaciers in glacial time between 

 Prescott and the Sierra Nevada. Probably 

 there were then small glaciers in some of 

 the cirques of northern exposure among the 

 mountains directly southeast of Prescott. 

 We may yet find that the glaciers reached 

 their southern limit in the Mogollon moun- 

 tains of New Mexico and Arizona, 



' The Pre-glacial Surface Deposits of 

 Lower Michigan ' : A. C. Lane. 



Some years ago in working out the gen- 

 eral system of drainage of the basin of the 

 Great Lakes, before it was disarranged by 

 the ice from the north. Professor J. W. 

 Spencer drew a sketch map indicating the 

 great streams flowing down to Lake Mich- 

 igan and Saginaw Bay and joining the 

 Lauren tian River, which flows off" across 

 Canada. In this scheme of drainage he has 

 been followed by most of the writers since, 

 and his work has been somewhat elaborated 

 by Mr. E. H. Mudge in an article in the 

 American Journal of Science, Volume 4, 1897, 

 page 383. There were, however, certain 

 arguments against the idea that the center 

 of lower Michigan drained through the Sagi- 

 naw Bay. Directly in the mouth of the 

 bay is a group of islands, the Charity 

 Islands, which are composed of cherty,. 

 sub-Carboniferous limestone, of about the 

 age of the Upper St. Louis. On both sides 

 of the bay occur outcrops of the same lime- 

 stone. The mouth of the bay is shallow,. 



