IOWA ACADEMY OF SCIENCES. 275 



number of species that it would be a mere accident to dis- 

 cover the organism. As said heretofore it seems to me to 

 be reasonable that the milk formed a favorable medium 

 for the growth of the organism, and be it specially remem- 

 bered that Mr. Briley, from his own testimony, failed to 

 wash the cans with boiling water as should have been done. 

 The milk cans could easily have been contaminated, and 

 the failure on his part to wash the cans, it seems to me, 

 made it not only possible but probable that these germs 

 propagated in the milk. 



A comparison of the water of the Briley well and the 

 college effluent shows that the Briley well had a greater 

 amount of contamination than the college effluent from the 

 sewage filter beds. 



DRIFT EXPOSURE IN TAMA COUNTY. 



BY T. E. SAVAGE. 



A few months ago, in making some improvements in 

 the roadbed of the Chicago & Northwestern Railroad, a 

 deep cut was made in a hill about three miles west of the 

 city of Toledo, in Tama county, Iowa, where the following 

 section was exposed: 



5. Fine giaineH, yellowish colored loess elaj without gravel or 



l)owlders 4^ 



4. Bed of sand in alternating bands of finer and coarser grained 



material 8 



3. Bed of clay, containing numerous pebbles and boAvlders 24 



2. Band of brown colored, somewhat sandy soil, containing 



impressions of vegetalile remains and a few bits of wood, 1^ 

 1. Bed of bjuisb colored clay, with numerous pebbles and 



bowlders down to the base of the exposure 16 



In the section given above. Number 5 is the common 

 fine grained loess that forms the surface soil over most of 

 the neighboring region. It contains no pebbles nor bowl- 

 ders, nor any calcareous matter, as shown by the want of 

 action when treated with hydrochloric acid. It is of a 

 yellowish color in the upper part, becoming tinged with 

 brown in the central and lower portions. 



