1922] Kellogg: Calif ornian Forms of Microtus Montmius 263 



As remarked in the introduction, Microtus nwntanus has an inter- 

 rupted distribution, being restricted for the most part to colonies in 

 wet meadows and apparently limited to the vicinity of Mount Shasta 

 and the Siskiyou Mountains of California. The subspecies montam,us 

 shows about the same range of individual variation as is exhibited 

 by yosemite and dutcheri. Specimens from Brownell and Tule Lake 

 are apparently closer to montanus than to yosemite. Specimens from 

 Dana and Fort Crook are apparently best disposed of hy referring 

 them to ynonitamis, while certain specimens from Cassel listed under 

 yosemite show an approximation to mo}itaniis. On the other hand 

 specimens from Bieber, Adin, and Pine Creek exhibit characters within 

 the limits of variation of yosemite. 



During the year 1855, Dr. J. S. Newberry collected the type of 

 Baird's Arvicola longirostris at some point between Fort Reading 

 and Fort Vancouver. He was then attached as geologist and botanist 

 to Lieutenant R. S. Williamson's party, which was making a survey 

 for a railroad route from the Sacramento River Valley to the Colum- 



1268 

 bia River. The type specimen, no. ^^„ , now in the U. S. National 



Museum, is labeled as having been collected during September, 1855, 

 on the upper Pit River. Various circumstances indicate that the 

 allocation of the name will be difficult. If the specimen was actually 

 taken on the upper Pit River, it was probably collected on the west 

 bank, somewhere north of the upper end of the canon (possibly near 

 Happy Camp). It seems hardly possible, however, that the type could 

 have been collected on the upper Pit River, for the explorers were in 

 Oregon by August 13, and arrived at Fort Vancouver on October 9, 

 1855. A brief account of their California explorations (Abbot, 1857, 

 pp. 56-75) will suffice to show that either the type was not collected 

 near the Pit River or else it was not collected during September, 1855. 

 They left Fort Reading on July 28, reaching McCumber's Flat (alt. 

 3600 feet) on Battle Creek on July 29. On July 30, 1855, the entire 

 party journeyed over the road which followed up Battle Creek, and 

 crossed the main mountain divide through Noble's Pass. From here 

 the party took the emigrant road down Lost Creek to its junction with 

 Canoe Creek (= Hat Creek) and thence, after following the latter 

 for some distance, crossed to a point on the bank of Pit River about 

 two miles above the mouth of Hat Creek. On Augl^st 5 they camped 

 on the south side of Pit River near the site of Fall River Mills. The 

 upper end of the Pitt River Canon was reached on August 7, and 



