1912] Taylor: Birds and Reptiles of Norfliern Nevada. 331 



high Transition. A few limber pines occurred below the level 

 of Alder Creek Lake (7800 feet), and occasionally the pene- 

 trating cries of Nucifraga columbiana sounded from the ridges. 

 About the lake itself a number of Boreal and Transition forms, 

 as Aphyllon fasciculatuni, Pentstemon confertus caeruleo-pur- 

 pureiis, Arnica chamissonis, and Pinus flexilis, were present. 

 White-crowned sparrows, olive-backed thrushes, Brewer spar- 

 rows, chipping sparrows and green-tailed towhees were common 

 at Camp no. 6, as were also Oregon ground squirrels. 



Biological Cross-section Camp no. 7 (6000 feet; see pi. 12, 

 fig. 2). — As progress was made down the creek the flora grew 

 more limited. In the neighborhood of this camp there was no 

 thick vegetation away from the stream. That along the creek 

 was made up of quaking aspens and willows, with occasional 

 thick tangles of Rosa and other vines. Alders appeared for the 

 first time on this stream not far below this altitude, and were 

 found scatteringly down to Alder Creek Ranch. 



Three species of mammals were taken here which make the 

 locality an extremely interesting one from a zonal standpoint, 

 namely, Neotoma cinerea occidentalis, Zapus princeps oregonus, 

 and Putorius cicognani. The olive-backed thrush, western war- 

 bling vireo, and green-tailed towhee were also noted. The ex- 

 posed ridges in the vicinity may be high Upper Sonoran, as 

 Sylvilagus nuttalli grangeri was secured on one of them. On 

 the other hand the Oregon ground squirrel ranges down below 

 the large Alder Creek Meadow (6700 feet) even on exposed 

 ridges. So, if the ridges are Sonoran at all they should be 

 regarded as high Upper Sonoran. There is little doubt that 

 along the stream Transition extends down to and beyond this 

 point. This remarkable association of Boreal, Transition and 

 Upper Sonoran forms, found at several points in the mountains, 

 is strikingly illustrated by the fauna of this locality. 



Biological Cross-section Camp no. 8 (5000 feet). — Willows, 

 with a few alders and aspens, made up most of the line of 

 vegetation along the creek in the vicinity of Alder Creek Ranch. 

 Treeless stretches were fairly common. The Artemisia associa- 

 tion of the open desert was more sparse and scattering here than 

 at any other point visited. 



