THE MUSEUM. 



II 



cordingly, we find the knoll which re- 

 sults from the uprooting of a beech or 

 a birch tree to be short, wide, not 

 very high, and rather flat. Spruce 

 and hemlock, and also pine, when it 

 grows on dry ground, all have short 

 roots, and of so feeble a tensile power 

 that they generally break. Thus the 

 knolls resulting from the uprooting of 

 Ihese trees are small. Again, when a 

 tree of any species is partially uprooted, 

 and lodges against another tree, a 

 knoll is formed which is always nearly 

 round and conical, thus betraying its 

 origin. 



I have, thus far, described only per- 

 fect knolls of each class. Modifica- 

 tions exist and so closely do they merge 

 that the line of demarkation cannot 

 always be reorganized. It is, howev- 

 er, a matter of little importance. It 

 would merely serve to show the spec- 

 ies of trees with which the country was 

 formerly covered — a matter of little 

 importance e.xcept in isolated cases. 

 Still, a stud}' of the knolls reveals 

 some important facts. For, as before 

 stated, they invariably show from 

 what direction the wind came, and, 

 also their comparative age. Now, if 

 we find a large number of knolls close 

 together, of the same age and e.xtend- 

 ing in the same direction, it follows 

 that, at some time in the past there 

 must have been a hurricane which 

 blew down all or nearly all the trees 

 upon that area. 



Acting upon its theory and by notic- 

 ing the similarity of knolls, I have 

 been able to trace the paths of two 

 hurricanes which visited this country 

 not far from one hundred and fifty 

 years ago, or about fifty years before 

 the settlement of the county. The 

 first of these storms come from the 

 northwest. It struck very nearly in 

 the northwest corner of the township 

 of Montpelier and swept a path half a 

 mile wide, diagonally across the entire 

 township. The timber was principal- 

 ly maple, and it is doubtful if a dozen 

 trees were left standing. The second 

 storm was much less extensive than 



the first. It originated about a mile 

 to the east, and coming more nearly 

 from the north, it swept a territory of 

 mi.xed, hard and soft wood, about a 

 mile long by forty rods wide. Besides 

 these I have discovered traces of sev- 

 eral other storms, but cultivation has 

 destroyed the knolls until it is impossi- 

 ble to map the extent of the hurricane. 



Land and Fresh Water Shells of 

 Dodge County, Wisconsin. 



BY WILL EDWIN SNYDER, BEAVER DAM, 

 WISCONSIN. 



Dodge County, Wisconsin, affords a 

 rich field for one who delights in Con- 

 chological research amon?; the Land 

 and Fresh Water Shells. Her several 

 lakes, streams and extensive marshes 

 all afford dwelling places for many 

 beautiful and interesting shells. 



The following list is by no means a 

 complete one, since my field of search 

 has been limited to Fox lake, eight 

 miles north of here, and within a radi- 

 us of three miles of my home. Hori- 

 con Marsh with its several thousand 

 acres has never been explored, nor 

 has Loss Lake and many of the 

 small streams. Very little has been 

 done toward collecting the Unionida;, 

 and many species can be added to the 

 list I am sure. In addition to those 

 given below I have four or five species 

 not yet determined. 



Before presenting the list I wish to 

 thank Mr. Chas. S. Hodgson and Dr. 

 Berlin Hart Wright for their kindness 

 in naming many of the species for me. 



Helix tmdtilincata Say, var. minor. 

 Abundant in one marsh that covers 

 at least lOO acres. All uniform in size 

 but variable in markings. 



Helix profunda. Say. Found abun- 

 dantly on two small islands in Fox 

 Lake. Principally found on Iinpaticiis 

 fiilva. 



Helix momlon, var. f rate ma. Say. 

 Abundant in the same marsh with H. 

 niultilincata, also in one smaller 

 marsh. 



Pupa armifera. Say. Commor 



