July 24, 1914] 



SCIENCE 



145 



distance while making some improvements in the 

 road-bed. 



The fresh section affords an excellent opportu- 

 nity for studying this phase of the Maquoketa 

 shales. Several feet of interesting beds higher up 

 than those described by the writers mentioned 

 have been exposed. The new section is described 

 and a revised list of the fossils is given. 

 The Surface Clay of Adair County (^Second 



Paper) : James E. Gow. 



Evidences of Sand Dune Formation in Cedar 

 Mapids and Vicinity: Washbuen D. Shipton. 



Pleistocene Exposures in Cedar Bapids, Iowa and 



Vicinity: WASHBuitN D. Shipton. 

 Preliminary Report of Geological WorTc in North- 

 eastern Iowa: Arthur C. Trowbridge. 

 Field work is now being carried on in northeast- 

 em Iowa by students and faculty of the geology 

 department of the State University of Iowa. 

 Much new material is being found, along the lines 

 of stratigraphic, structural, paleontologic, eco- 

 nomic and physiographic geology. The region is 

 particularly rich in physiographic problems, and a 

 continuation of the work is expected to yield much 

 additional knowledge of the Mesozoic and Ceno- 

 zoio history of this part of North America. 

 The Origin of EsTcers: Arthur C. Trowbridge. 



There are many difficulties with the generally 

 accepted subglacial theory for the origin of eskers, 

 which says that these interesting ridges are de- 

 posited by streams flowing beneath continental 

 glaciers. It seems more likely that they are 

 formed by the slow recession of the edges of gla- 

 ciers during the deposition of kames, and a result- 

 ing drawing out of the kames into long lines. 



An Area of Wisconsin Drift farther South in 

 Polk County, Iowa, Than Hitherto Recognised: 

 John L. Tilton. 



One mile south of the bridge over Eaecoon 

 Eiver at Valley Junction there is a small area of 

 Wisconsin drift about a third of a mile in diam- 

 eter. 



Indian Pottery of the Oneota or Upper Iowa Val- 

 ley in Northeastern Iowa: Ellison Ore. 

 The Oneota or Upper Iowa, a small river about 

 eighty miles in length, flows through Winneshiek 

 and Allamakee counties in Iowa close to their 

 northern border, which is also the line between this 

 state and Minnesota. It flows through a beautiful 

 winding valley which has a width of half a mile, 

 and is bounded by precipitous bluffs. The glacial 

 terraces which extend up this valley for forty 



miles to Decorah have afforded very abundant evi- 

 dences of a former considerable Indian population. 

 Earth embankments, mounds and camp sites have 

 yielded up a treasure of implements, weapons and 

 ornaments. Notable among these are the large 

 number of small earthen vessels found in burial 

 places and the fewer large ones which seem to have 

 been buried by themselves. The writer has been 

 quite successful in finding or securing a number 

 of well-preserved specimens of both classes, some 

 of which he describes in detail. The material used 

 in the manufacture was common clay tempered by 

 pulverized clam shells. In shape this pottery is 

 symmetrical but the attempts at ornamentation are 

 crude. The vessels all have a rounded pot-like 

 bottom and if upset, will at once resume an up- 

 right position. "In short, these prehistoric pot- 

 ters, while they were able to produce very shapely 

 ware, were unable to add to its beauty by elabo- 

 rate, intricate or symmetrical designs." The 

 paper is illustrated by nine plates. 



Longitude ty Wireless: D. W. Morehouse. 



Illumination Power of Kerosenes Used in Iowa: 



William Kunerth. 



The results of this series of experiments can be 

 summarized as follows: 



1. By the application of ordinary photometric 

 methods great differences in the illuminating power 

 of different samples of kerosene oils have been 

 shown. 



2. Oils from the east have a lower density and 

 are sold at a higher price than those from the 

 west. 



3. Those oils which have a high illuminating 

 power were found also to be high in density, in- 

 dex of refraction, viscosity, surface tension, flash 

 point and burn point. The length of wick charred 

 was shorter and the fogging of the chimney was 

 more marked than for the oils having low illumi- 

 nating power. 



4. The oils which were retailed at lower cost 

 gave more light. 



5. By putting coloring matter into an oil the 

 illuminating power is decreased. 



6. By exposing oil to light, the illuminating 

 power is decreased. 



7. Draft reduces the illuminating power. 



8. The denser the oil the greater is the intrin- 

 sic brilliancy of the flame. 



9. Air in oil seems to decrease the illuminating 

 power. 



10. For a given flux of light the cost of illumi- 

 nation by kerosene oil lamps is about the same as 

 that by tungsten lamps. 



11. The oils used in this state have practically 

 the same burning quality. 



12. Kerosene oil lamps are not very desirable as 

 standards of comparison. 



13. The quantity of oil received for a gallon is 

 often very deficient. 



