June 15, 1906.] 



SCIENCE. 



919 



G. L. Cannok : ' The Necessity for Science Con- 

 ferences in Colorado.' 



Junius Henderson : ' The Collecting of Mol- 

 lusks in Colorado.' 



T. D. A. CocKEBELL : ' The Fossil Beds of 

 Florissant.' 



A. E. Beaedslet: 'The Crustaceans of Colo- 

 rado.' 



H. E. Sovereign : ' Apparatus illustrating the 

 Laws of Electromagnetic Induction.' 



A. N. Finn : ' A Report on the Quantitative 

 Analysis of Uranium and Vanadium.' 



J. Aethue Biechlet : ' A Study of the Kater 

 Pendulum.' 



Wm. Duane : ' New Kinds of Radiation.' 



G. S. DoDDS : ' The Projection Microscope for 

 Work in Botany and Zoology.' 



W. D. Engle: 'The Effect of Bile on the Sur- 

 face Tension of Water.' 



George I. Finlet: 'Recent Geological Correla- 

 tion Work in the Canon City Field.' 



Philip Fitch : ' A Review of the Development 

 of the Modern Kinetic Theory of Gases as a Basis 

 for the Study of Radioactivity.' 



F. L. Abbott : ' Producer-gas and Producer-gaa 

 Engines.' 



J. Vincent Daniels : ' A Report on the Forma- 

 tion of Malic Acid by Fermentation.' 



All of the institutions in the state of col- 

 legiate grade were represented by delegates, 

 and a number of the larger high schools as 

 well. A public address was given by Pro- 

 fessor Thomas H. MacBride, of the State Uni- 

 versity of Iowa, his subject being ' The Ee- 

 sponse of Plants.' Francis Eamaley, 



8'ecretary, Local Committee. 



DISCUSSION AND CORRESPONDENCE. 



A PERSISTENT ERROR. 



My attention has recently been called to an 

 error in the use of geologic names, which, 

 since I am inadvertently responsible, it seems 

 desirable I should correct. 



The terms Des Moines and Missourian have 

 been in use for some years, especially in the 

 publications of the Iowa and Missouri Sur- 

 veys, for the lower and upper coal measures 

 of the older classification. When I prepared 

 for the 22d Annual Eeport of the U. S. Geolog- 

 ical Survey a brief discussion of the western 

 interior coal field, I was located in a mining 

 camp with no opportunity for stenographic 



services. The report was, therefore, written 

 out in long hand and sent down to Washington 

 to be copied. Instead of being returned to 

 me it went through the press, and I had no 

 opportunity to examine it until the printed 

 copies came to hand. It seems that in one of 

 the early pages of the manuscript, by some in- 

 advertence I had transposed the terms. The 

 editor with painstaking care transposed them 

 through all the remainder of the manuscript 

 to correspond to this one wrong usage, and 

 they appeared in this form in the published 

 paper. The mistake was to my mind so 

 obvious, and the usage so well established, 

 that I never considered it worth while to make 

 the correction. However, it misled Dr. Buck- 

 ley, of the Missouri Survey, and in his report 

 on the quarry industry the terms are accord- 

 ingly misused. His attention having been 

 called to this, the following note was made in 

 the Geology of Moniteau County, page 8 : 



Attention is here called to the names Missourian 

 and Des Moines, in the use of which there is evi- 

 dently some confusion. In the earlier reports 

 of the Iowa and Missouri Geological Surveys the 

 term ' Missourian ' has been applied to the upper 

 coal measures, and the term ' Des Moines ' to the 

 lower coal measures. In the late reports of the 

 U. S. Geological Survey {22d Annual Report, 

 part 3, plate 22, page 341), their use has been 

 reversed, the term ' Missourian ' being applied to 

 the lower coal measures, and the term ' Des 

 Moines ' to the upper coal measures. These 

 names were iirst applied in the Missouri reports 

 during the Keyes administration, and there ap- 

 pears to be no good reason for reversing their 

 application. 



This would seem to have been sufficient to 

 make the matter clear, but in the report of the 

 coal-testing plant of the U. S. Geological Sur- 

 vey, Professional Paper 48, page 74, the wrong 

 usage again appears. I desire, therefore, to 

 enter protest in public against the persistence 

 of the usage, which was a typographical mis- 

 take to begin with, and for which there is, 

 as Dr. Buckley says, no good reason. 



H. Foster Bain. 



the northern limit of the papaw tree. 

 The article by Dr. C. A. White in the May 

 ll^issue of Science on the northern limit of 



