Occasional Papers of the Museum of Zoology 19 



Brook, a little over a mile above the junction with the East 

 Branch. On the sixteenth of August numerous freshly-dead 

 shells were found scattered along the very soft, muddy banks 

 of this creek. All of these were specimens of Pliysa gyrina 

 and had apparently been washed on the banks during a recent 

 flood. 



Pine Creek 



Habitat 2^. Pine Creek. This creek near Norway is about 

 25 feet wide and about two feet deep, and has quite a swift 

 current and a sandy bottom. A few years before an attempt 

 had been made to float logs down the stream, with the result 

 that it was so choked with them that one could walk over its 

 surface. 



Hancock Creek 



Habitat 2=,. Rocky and Stony Bottom. The Foster City 

 road crosses Hancock Creek near the old Hancock mine, 

 around which were considerable outcroppings of iron-bearing 

 rocks. In this place the bottom of the creek is rocky, with 

 sand gathered in the spaces between the rocks ; the current is 

 quite swift. Physa gyrina was found on the rocks and the 

 other species were burrowed in the sand patches. 



Habitat 26. Sandy and Mucky Bottom. Below the beaver 

 pond Hancock Creek meanders through swampy, rich alluvial 

 flats towards the Sturgeon River. The current is not very 

 swift and in many places the sandy bottom is covered with a 

 deposit of organic muck, composed of decaying twigs and 

 leaves which in places reached a depth of a foot. 



Habitat 27. Beaver Pond. About two miles above its mouth 

 Hancock Creek has been dammed by the beavers to form a 

 quite extensive pond, which attained a depth of eight feet, 

 This dam had been built quite recently as the flooded tama- 



