674 



SCIENCE 



[N. S. Vol. III. No. 70. 



is accompanied by a plate. W. H. Weed and 

 L. V. Pirsson give a continuation of their paper 

 on the Bearpaw Mountains of Montana, com- 

 menced in the April number. This is devoted 

 to the discussion of the Beaver Creek core with 

 reference to the massive rocks there present. 

 These are of various types, ranging from quartz 

 syenite and quartz syenite poryhyry to basic 

 syenite (or, as the rock has been called by 

 Brogger, monzonite), and finally to shonkinite. 

 It is remarked by the authors that their yogoite 

 already described from Yogo Peak, Montana, 

 is essentially identical with monzonite, and 

 hence the latter name has priority. 



M. Carey Lea has two brief articles. The 

 first discusses the question of the presence of 

 Kontgen rays in the sunlight, and decides this 

 in the negative. A number of conclusive ex- 

 periments are described, upon which this de- 

 cision is based. The second article is on the 

 numerical relation existing between the atomic 

 weights of the elements, especially with refer- 

 ence to the colored and colorless character of 

 the ions. This last subject was discussed by the 

 same author in the American Journal for May, 

 1895, and a second paper is promised for June 

 of this year. W. B. Clark describes minutely 

 the Potomac River section of the Middle At- 

 lantic Coast Eocene, showing the seventeen 

 divisions identified in the detailed stratig- 

 raphy of the deposits as exhibited par- 

 ticularly between Aquia Creek, Stafford county, 

 Virginia, and Pope's Creek, Charles county 

 Maryland. It is concluded that the Eocene de- 

 posits of the Middle Atlantic slope constitute a 

 single geological unit which has been described 

 as the Pamunkey formation. The deposits are 

 remarkably homogeneous, consisting typically 

 of glauconitic sands and clays of a thickness of 

 nearly 300 feet. There are two well-defined 

 faunal zones, namely, the Aquia Creek stage 

 and the Woodstock stage. The former approxi- 

 mately corresponds to the middle, or middle 

 and upper, Lignitic, and the latter to the middle, 

 or middle and upper, Claiborne. The author 

 concludes by remarking that the middle At- 

 lantic slope Eocene undoubtedly represents in a 

 broad way all of the major part of the Lignitic, 

 Buhrstone and Claiborne of Smith and, when 

 the physical condition afiecting range and mi- 



gration of species are considered, perhaps eveni 

 more. Both the geological and paleontological 

 criteria are wholly inadequate for establishing 

 the great number of local subdivisions recog- 

 nized in the Gulf area, and in fact the sequence 

 of forms indicates that no such differentiation 

 of the fauna took place. 



H. S. Washington describes some peculiar 

 Ischian trachytes with special reference to cer- 

 tain remarkable branching forms exhibited by 

 the feldspar phenocrysts ; these are analogous 

 to the feather-aggregates of augite which have 

 been described in some Hawaiian basalts. For 

 such divergent crystal forms, which are re- 

 garded as due to the ramification and growth 

 of a single individual, and which correspond to 

 the sphferokrystalle of Lehmann and Rosenbusch, 

 the name keraunoid (Gr. Kepavvoc, a thunderbolt), 

 is proposed. The existence of such forms has 

 been explained by Lehmann as due to internal 

 tensions which cause the crystals to split here 

 and there at the surface, producing a discon- 

 tinuity which cannot be overcome by further 

 growth. The author adds the results of his 

 own observations as modifying and extending 

 the results of Lehmann, and concludes by con- 

 sidering the various types of spherulites in 

 general. The articles close with a paper by C. 

 Palache describing some highly modified crys- 

 tals of crocoite, from a hitherto undiscovered 

 locality in Tasmania. 



AjMerican chemical journal, apbil. 



The action of light on some Organic Acids in the 

 presence of Uranium salts. By Henry Fay. 

 After reviewing previous work on this sub- 

 ject the author gives the results obtained with 

 oxalic, butyric, propionic and acetic acids. 

 From oxalic acid he obtained carbon dioxide, 

 carbon monoxide, formic acid and several ura- 

 nium compounds. When the acids of the acetic 

 acid series were used, equal parts of carbon 

 dioxide and the hydrocarbon corresponding to 

 the acid were formed. Succinic and malonic 

 acids could not be used on account of the in- 

 solubility of the uranium compounds. 



A review of some recent work on Double Halides. 

 By Charles H. Herty. 

 In this paper attention is called to the char- 



