1916] Kellogg: Mammals and Birds of Northern California 369 



than that at Helena, and was again in sandy ground, in the old 

 bed of the Scott River, but nearly a mile back from the present 

 main stream which, according to report, had been at one time arti- 

 ficially diverted to its present bed. Numerous small creeks and 

 back waters of the river, are, however, on this side of the valley, 

 used for irrigation. Some of the land is under cultivation, but a 

 great deal consists of sand, overgrown with cottonwoods and willows 

 and is used for pasture. The kangaroo rats here seemed to prefer 

 the thicker brush for their headquarters, but Miss Alexander was 

 most successful in securing specimens by setting the traps in a 

 horse trail, to which the animals were no doubt attracted by the 

 grain to be gathered from the droppings. 



Zapus trinotatus alleni Elliot 

 Allen Jumping Mouse 



A series of sixty-three specimens of this species was obtained 

 (nos. 13696-13758), from the following localities: Jackson Lake, 

 North Pork of Coffee Creek, Saloon Creek divide, South Fork of 

 Salmon River, head of Grizzly Creek, head of Rush Creek, head 

 of Bear Creek. The series is remarkable for the freshness and uni- 

 formity of the pelage and the fact that nearly all the specimens 

 are adult. In some groups of mice, such as Microtus and Peromys- 

 cus, nearly as many young ones as adults are taken, but in our 

 trapping we did not take a single very young specimen of Zapus 

 in spite of the fact that some of the females showed signs of having 

 bred. 



Another rather singular fact was that we never saw any signs 

 of Zapus, such as runways, excrement or cuttings, and yet we 

 caught some individuals at every camp where there were meadows 

 or alders along running water, from an elevation of 4500 feet, on 

 the North Pork of Coffee Creek, to our highest camp at Jackson 

 Lake, 7200 feet. The species was most abundant at Coffee Creek, 

 where we secured half of the whole series. We always found them 

 in places where the vegetation was rank, generally, as just stated, 

 under alders. 



Aplodontia chryseola Kellogg 

 Trinity Mountain Beaver 

 Ten specimens secured (nos. 13324-13332, 13806) from Jackson 



