Geology and Natural History. 395 



contamination, it was found that hydrogen transmits the shortest 

 waves as well as a vacuum. — Ann. der Physik, No. 3, 1901, pp. 

 642-645. J. t. 



11. Measurement of the Rontgen Rays by means of Selenium. — 

 F. Himstedt, in an investigation on the X-rays and the Becquerel 

 rays, shows that these rays alter the resistance of selenium, and 

 he hopes to devise a plan for the qualitative measurement of these 

 rays. — Ann. der Physik, No. 3, 1901, pp. 531-536. J. t. 



12. The Effect of the Rontgen Rays and the Becquerel Rays on 

 the Eye. — Giesel has shown that a preparation of radium laid 

 upon the eyelid gives a sensation as if the entire eye was filled 

 with light. F. Himstedt and W. A. Nagel have made a careful 

 examination of this phenomenon, and also of the effect of the 

 X-rays on the eye. They show that a fluorescence is excited in 

 the organs of the eye which produces the sensation of light. 

 Their work confirms the investigations of previous observers and 

 somewhat extends them. — Ann. der Physik, No. 3, pp. 537-552, 

 1901. J. T. 



II. Geology and Natural History. 



1. The Eoce?ie and Lower Oligocene Coral Faunas of the 

 United States, with descriptions of a few doubtfully Cretaceous 

 species; by T. Wayland Vattghan. Monograph, vol. xxxix, 

 pp. 263, 24 pi. U. S. Geological Survey. Washington, 1900. — 

 Upon taking up the study of the Tertiary corals, Mr. Vaughan 

 set for himself the task of defining every species presenting 

 good and identifiable figures, showing their stratigraphic range 

 and geographic distribution ; then, secondly, he sought to deter- 

 mine from the study of the corals, the bathymetric conditions 

 under which they lived and were buried ; and thirdly, to trace, 

 so far as practicable, the affinities of the forms met with. He 

 brought to the solution fine equipment and excellent collections, 

 and has performed his task well. The descriptions and delinea- 

 tions of species appear to be all that could be wished for. The 

 questions : what is a species ? and how to classify corals ? have 

 been conscientiously met and judiciously handled, but the author, 

 like other workers in this field, leaves the burden of proposing 

 something better than the current system to those who will 

 follow. 



The study of the bathymetric distribution of the species on a 

 basis of known depths at which corresponding genera are now 

 living leads to the conclusion that the faunas of the Eocene and 

 Oligocene under investigation lived at only moderate depth, not 

 over 100 fathoms, and 18 out of 24 genera now live in water less 

 than 50 fathoms deep. The author gives valuable statistics 

 regarding the bathymetric values of the faunas of the several 

 formations studied. An excellent account of the morphology of 

 the Madreporarian coral skeleton is given, which will be helpful 

 to students. 



The volume is a distinct contribution to the systematic knowl- 

 edge of Tertiary corals. w. 



