JANI'ARY 3, 1896.] 



SCIENCE. 



31 



SCIENTIFIC JOURNALS. 

 JOURNAL OF GEOLOGY, NOVEMBER-DECEMBER. 



The Greenland Expedition of 1S95 : By R. D. 

 Salisbury. This is not an itinerary of the ex- 

 pedition, but a discussion of the geologic and 

 geographic problems suggested in the course of 

 it. The following are considered : coastal to- 

 pography and its interpretation, evidence con- 

 cerning past glaciation from nature of rock sur- 

 faces, general distribution of snow and ice, ice- 

 bergs and evidences concerning recent changes 

 of level. The time allowed was not sufficient 

 for detailed observation on any of these lines, 

 but the facts gathered are of especial significance 

 as supplementing and checking as well the work 

 of last summer in this little known field. The 

 author finds strong evidence that the Pleistocene 

 ice sheet of America did not come from Green- 

 land, and that the conditions for glaciation on 

 the coast of Greenland to-day are better in lati- 

 tude 74°-76°than in 76°-79°. Another interest- 

 ing conclusion is that the ice cap of Greenland 

 did not reach its greatest extension at all points 

 at the same time. The observations on ice- 

 bergs are quite full and show clearly either that 

 there was little debris in the parent glaciers, or 

 that it was quickly lost by the bergs. 



A Cireum-Insiilar Paleozoic Fauna : By S. 

 Weller. So long as paleontology made the 

 identification of species an end in itself and as- 

 sumed that forms found widely separated in 

 space must belong to different species, even 

 though they seemed to be identical, it was neces- 

 sary doubtless, but it was not interesting to the 

 philosophic geologist, because it seemed to him 

 to ignore more than it considered. In later 

 years there has been a decided broadening in 

 the view of paleontologists. Under the lead of 

 Williams, Walcott and Smith in this country 

 there has been an attempt to solve the same 

 kind of problems for ancient faunas and floras 

 which Wallace, Dal'win, Gray and others have 

 solved for modern ones. In this paper the 

 author applies the method in determining the 

 origin of the Chouteau fauna of the Ozark area 

 in southeastern Missouri. He finds evidence of 

 a land barrier extending from ' Isle Wisconsin ' 

 southwest through this area in early Devonian 

 time which separated two rather distinct faunas. 

 In the latter part of the Devonian this land 



barrier became sea bottom, and the two faunas 

 mingled freely in tlie Ozark area. The result 

 was a new fauna decidedly Carboniferous in its 

 affinities, though Devonian in time. The most 

 hardy elements of the two competing faunas 

 survived, and this new vigorous stock gave 

 character to succeeding faunas for a long period. 

 Some pregnant suggestions are made regarding 

 correlation of formations. 



Experiments in Ice Motion : By E. C. Case. 

 The mechanics of glacier motion involve ques- 

 tions often asked but not easy to answer. The 

 experiments of the author were designed to 

 throw light on the existence and nature of 

 differential movement in the basal portions of 

 glaciers. Paraffine Avith a quantity of refined 

 petroleum to lower the melting point was the 

 material used. It was placed in a box with 

 various obstructions in the bottom and by 

 means of a close fitting plunger was forced 

 toward the middle of the box over the obstruc- 

 tions. In order to trace the currents, thin lines 

 of powdered coal or Galena, and layers of dark 

 wax, were used. The results, as shown by the 

 photographs, tally well with Prof. Chamberlin's 

 descriptions of some Greenland glaciers. The 

 author finds proof of both vertical and hori- 

 zontal differential movements in the basal por- 

 tion of the wax. Similar currents in glaciers 

 he thinks may be the cause of certain features 

 of suhglacial topography. For example, he 

 iinds that drumlin areas lie in the lee of escarp- 

 ments or other irregularities of hard rock over 

 which the ice has just passed. 



Absarokite-Shoshonite-Banakite Series: By J. 

 P. Iddings. This is a study of a peculiar series 

 of igneous rocks associated with the normal 

 andesites and basalts of the Yellowstone Na- 

 tional Park, but diflfering from them mineral- 

 ogically and chemically. These rocks are ar- 

 ranged under the three groups named in the 

 title, of Avhich the first contains the least SiO, and 

 the third the greatest amount. The author 

 concludes that this is a series variable in two 

 principal directions chemically : in the ratio of 

 alkalies to silica, and also in the silica percent- 

 ages. The variations of other chemical con- 

 stituents are to some extent functions of these 

 variables. 



Distribution of Oold Deposits in Alaska: By 



