198 



vegetation is scanty or altogether absent. The fauna and flora 

 here are so distinctly western that this tract might almost be 

 considered as a detached islet of the Upper Sonorau life zone. 



The other localities most frequently visited, were (1) the 

 Devil's Hole (PI. XIII.; XIX., Fig. 1; XX., Fig. 2), a similar but 

 much smaller tract of blow-sand a mile or so east of Havana; 

 (2) the exceptionally broad area of very sandy land south of 

 Havana (PI. VIII.-XL, XV.-XVIL), with numerous small tracts 

 of blow-sand and large bodies of black-jack timber; (3) the less 

 sandy and better-forested submarginal ridges, often fifty feet or 

 more in height, which extend through Havana, especially those 

 a mile or two north of the city, in the vicinity of Quiver Lake 

 (PL XXL, Fig. 2); and (4) the moist sand strip at the base of 

 the low marginal bluff of the sand plain ( PI. XXII 1.), saturated 

 more or less extensively with outflowing ground-water, in part 

 forming the east shore of the river and of bottom-land lakes 

 bordering on the sand plain. 



Two additional localities, both at a considerable distance 

 from Havana, were visited in 1905. One of these was Meredo- 

 sia, near the southern end of the central basin, about forty-five 

 miles below Havana, A small tract of blow-sand, with a few 

 blowouts and some black-jack, lies immediately south of the 

 town, and the distinctive sand fauna observed about Havana 

 seemed well represented here also. Aside from this, there 

 seemed to be very little blow-sand in the vicinity. The other 

 locality was the Moline Sand Hill, described by McNeill ( '91. 

 p. 73). This extends along the Rock River, near its mouth, 

 only a few miles from the city of Moline, on the Mississippi, 

 just across the narrow intervening divide. It is a conspicuous 

 elongate sand-hill, about a quarter of a mile long, near the 

 south bank of the river. At the east end of the crest is an acre 

 or two of undisturbed waste land, with a group of several good- 

 si zed blowouts, bordered by a small fringe of willow and Caro- 

 lina poplar on the east slope of the hill. The sand is here ap- 

 parently finer than at Havana. The fauna differs slightly from 

 that of the Illinois valley regions, but not to any marked de- 

 gree. While there are other and larger blow-sand areas in this 



