100 Trans. Acad, Sci. of St. Louis. 



consin Eiver has cut for itself a devious channel in this rock, 

 from 100 to 150 feet in depth and from 52 feet to half a 

 mile in width. The area studied embraces a tract bordering 

 the river for about four miles in the Lower Dells and about 

 three and a half miles in the Upper Dells. 



The locality is a notably picturesque one, characterized by 

 canons, glens and ravines which have been cut by small 

 streams flowing into the Wisconsin Kiver. These lateral 

 canons and glens are from 100 to 140 feet in depth and vary 

 from a few rods to over a mile in length. The sides of the 

 canons are very precipitous and frequently almost meet in 

 some places, forming passages such as '* Fat Man's Misery" 

 in Cold Water Canon. The walls are overgrown with moss, 

 ferns and lichens and present an enticing spot for the 

 botanist. 



The reported character of the country, a Potsdam sandstone 

 covered with coniferous trees, had led me to expect a very 

 poor fauna, especially insects and mollusks. I was consider- 

 ably surprised, therefore, upon studying the region, to find 

 both a varied and abundant fauna, not only of the inverte- 

 brates, but of the vertebrates as well. This diversity of life 

 is probably due to the abundance of deciduous trees, the 

 fallen logs and branches of which become soft and afford 

 ample protection for many small animals. In the glens and 

 canons the greatest variety is found, although the wooded 

 plateaus between the canons and glens also support a rich 

 fauna, especially of insects and spiders. The whole region is 

 a curious mixture of coniferous and deciduous trees. Id some 

 places the two kinds are mixed together, while in others each 

 kind occupies a separate and restricted area. Fungi, 

 lichens and mosses are everywhere abundant and the ground 

 is moist about the decaying tree trunks, affording excellent 

 retreats for the smaller land snails. 



We have been led to declare, as a rule, that snails will not 

 flourish in a sandstone region, and particularly in a locality 

 where pine trees are abundant, but the Dells region is an 

 exception to this rule, for snails were found here under logs 

 which lay on beds of pine needles, in the midst of pine 

 woods. 



