PUBLIC PARKS OF IOWA 163 



YELLOW RIVER REGION IN ALLAMAKEE COUNTY. 

 BY L. H. PAMMEL, BOTANIST. 



The area about Myron must be considered separately. With Ellison Orr 

 and D. O. Wilson, a day was spent early this summer in an investiga- 

 tion of this interesting region. The area here considered is on the 

 north slope of a hill, with the Yellow river flowing at its base. The Yel- 

 low river is a 'Stream of considerable size, having its source from sev- 

 eral streams from one-half to three-quarters of a mile above the place 

 where the Balsam fir occurs. Temperature records taken of the soil 

 . one inch down at random indicated that the soil was much cooler than 

 that of the surrounding woody hills and bluff's. The limestone rock is 

 extremely porous and all through it are caverns of various sizes. From 

 these caverns during the summer cold air is constantly issuing. At one 

 point where the rock was covered with mosses, consisting of Hypnum 

 tamarisicinum and Anomodon minor, the temperature was 46 degrees F. 

 The highest temperature found in open places was 63 degrees, at a 

 depth of one inch. At other points the temperature varied from 56 de- 

 grees to 60 degrees, showing that one of the most important factors in 

 connection with the boreal plants developed here is the temperature. 

 The temperature of the air was 75 degrees. 



The stretch of Balsam fir woods extends from about one-half to three- 

 quarters of a mile on the north slope of a hill. The Balsam fir, the White 

 pine, Pyrus arbutifolia, Corylus rostrata, Diervilla trifida, Betula papyri- 

 fera, Lonicera glauca, Aralia quinquefolia, A. racemosa, Bromus pur- 

 gans, Poa memoralis, Campanula Taxus cnadensis, Sambucus racemosa. 

 Phegoteris calcarea, Acer spicatum, Aconitum uncinatum, Viola blanda, 

 Saxifraga pennsylvanica and Arabis lyrata were distributed through- 

 out the region. The Poa nemoralis, Arabis lyrata and Campanula ameri- 

 cans occurred upon the limestone rocks with little soil. They occurred 

 with numerous 'species of lichens, of which the following are prominent: 

 Buellia albo-atra, Lecanora privigna, L. calcarea var. contorta and L. 

 muralis var. versicolor. The Polpydium vulgare, Circaea alpina and 

 Cypripedium pubescens were more or less local. Most of the lime- 

 stone rock has become covered with vegetation. It is only in the drier 

 places that the A-rabis lyrata thrives. The Saxifraga pennsylvanica, Viola 

 blanda and Bromus kalmii occur in the moister places. 



THE BACKBONE, MADISON COUNTY. 

 By James H. Lees, Geologist. 



The Backbone, on Middle river in Madison county, is a charming 

 'bit of scenery cut out of the one time level plain of south central Iowa. 

 It represents the erosive activity of the stream, working through many 

 centuries and swinging in ever widening curves. It is located in sections 

 15 and 16 of Lincoln township, four or five miles southwest of Winter- 

 set, from which town it is readily accessible . and where it is justly 



