October 6, 1893.] 



SCIENCE. 



193 



June 9, 1893,) is twenty-five miles by the river above 

 Trenton, these much smaller and less noticeable workings 

 lie only fourteen miles inland east northeast from the site 

 of the celebrated gravel discoveries. 



Neshaminy Creek iiows into the Delaware (right bank) 

 about three miles below Bristol, (Bucks Co., Pa.,) and a 

 walk to the quarries by following up the winding stream 

 from the river would cover a distance of about twenty 

 miles. 



BOOK-EEA'IEWS. 



Iowa .Geological Survey, Volume I: First Annual Report, 



for 1892. By Samuel Calvin, State Geologist, Des 



Moines, 1893. 472 p., 8vo. 10 plates and 26 figures. 



In addition to the administrative reports, the first re- 

 port of the new survey contaias seven papers, one of which 

 is by the state geologist, three by the assistant 

 state geologist " C. R. Keyes, and the others by 

 various members of the survey staff. The introductory 

 paper, by Mr. Keyes, on the Geological Formations of 

 Iowa is a summary of present knowledge of Iowa rocka. 

 The author has here taken occasion to revise the classifi- 

 cation of these formations to correspond with the progress 

 made in their study in recent years with a very satisfac- 

 tory result. 



The Sioux quartzite is referred to as a doubtful element 

 still in the geological section. The discovery of un- 

 doubted eruptive rock within these beds in southeastern 

 Dakota by Culver and Hobbs, and in presumably the 

 same beds in northwestern Iowa \)Y the present survey, 

 as set forth in fuller detail in Mi-. S. W. Beyer's paper, is 

 a matter of much interest and tends to add probability to 

 the view entertained by Hayden that these rocks are much 

 younger than commonly supposed. 



The changes in nomenclature are much for the better, as 

 for example, Oneata for Lower Magnesian; St. Croix for 

 Potsdam; while in the Devonian the attempt to correlate 

 the Iowa rocks with the New York section is abandoned. 

 Prof. Calvin's work upon these formations has resulted in 

 a four-fold division with names from places where the best 

 sections are shown. 



In the Lower Carboniferous, or Mississippian, the term 

 Augusta is advocated for the terrane which Williams 

 called the Osage, a name here shown to be inapj)licable. 

 We would dilfer with the author as to the advisability of 

 dropping the term Warsaw as a sub-division of the 

 Augusta in so far as concerns the rocks of Iowa, for 

 though probably of limited development they present 

 constant and easily recognized characters through- 

 out the southeastern part of the state. An error 

 occurs in the definition of the St. Louis limestone on 

 page 72. The brecciated limestone is not the basal 

 member, as asserted by the author, but in many sections 

 along the Des Moines River there is shown to be from five 

 to fifteen feet, or more, of a brown, quite regularly 

 bedded magnesian limestome underneath the brec- 

 ciated member and resting upon the arenaceous division 

 of the Warsaw beds below. 



In his discussion of the structure of the Coal Measures 

 the author presents a valuable contribution to the litera- 

 ture of this subject, and advances conclusions acceptable 

 alike for their simplicity and adherence to generally ac- 

 cepted princijsles of dejjosition. 



The description of the Cretaceous formation is pro- 

 fessedly taken from Professor Calvin's notes. Evidence 

 is accumulating to show that these rocks have a much 

 greater development in Iowa than heretofore considered. 

 Three divisions are recognized and correlated with 

 Hayden's Dakota. Fort Benton and Niobrara groups. 

 The position of the Fort Dodge gypsum beds and the 

 Nishuabotua sandstone are left undetermined. 



In Mr. Beyer's paper there is given an account of the 



discovery in a deep well at Hull, Sioux County, Iowa, of 

 quartz-porphyry — an eruptive rock, interstratified with 

 sandstone. It occurred all the way from seven hundred 

 and fifty-five feet down to twelve hundred and twenty 

 feet, aggregating about one hundred and eighty-seven 

 feet in thickness. To account for the presence of these 

 rocks, the author advances two theories: (1) that they 

 were due to secular outflow of lava upon the ocean 

 bottom in Palseozoic times, (2) that they represent 

 intrusive subterranean sheets from a Post-Car- 

 boniferous volcano. The latter view is considered 

 the most probable. In the absence of evidence as to the 

 age of the sandstones, however, we see no reason why a 

 third view may not be entertained, viz., that they were 

 secular overflows from a Post-Carboniferous volcano. 



In Mr. H. F. Bain's paper we have an interesting and 

 instructive discussion of the St. Louis limestone as found 

 in Mahaska County, Iowa, while Mr. G. L. Housen's paper 

 deals with the economic phases of some Niagara lime- 

 stones. 



An Annotated Catalogue of Minerals and a Biblio- 

 graphy of Iowa Geology by Mr. Keyes, complete the 

 volume. The latter paper occupies more than half of the 

 report and shows evidence of much care and jiainstaking 

 labor, though a paper by the writer on the Keokuk lime- 

 stone, published in the American Journal of Science for 

 October, 1890, has evidently escaped the attention of the 

 author. 



The report has been printed from new and excellent 

 type, the illustrations are exceptionally good, and alio- 

 gether the volume in its make-up presents a pleasing con- 

 trast to many similar publications. 



Typographical errors are not uamerous, though some 

 occur in prominent places, as, for examaple, in the word 

 Survey on the title page, and in the words Tennessee and 

 Territory on plate VI, though these can hardly be con- 

 sidered typographical. Errors appear also in the words 

 Sandstone, p. 149, and Glacial, p. 139. A further 

 criticism might be made on the lettering on the back of 

 the volume, which scarcely seems in keej)ing with the 

 pleasing effects of the text. But these are minor matters, 

 and the survey and the state are to be congratulated up- 

 on the general excellence of their first report. 

 The Microscope : Its construction and management. In- 

 cluding Technique, Photo-micrography, and the Past 

 and Future of the Microscope. By De. Henki Van 

 Heukck, Professor of Botany and Director at the Ant- 

 werp Botanical Gardens; late President of the Belgian 

 Microscopical Society; Hon. F. R. M. S. and New York M. 

 S. English edition re-edited and augmented by the 

 author from the fourth French edition, and translated by 

 Wynne E. Baxter, F. R. M. S., F. G. S. With three plates 

 and upwards of 250 illustrations. London, Crosby, Lock- 

 wood & Son, New York, D. Van Nostrand Co., 1893. 

 382 p., Roy. 8vo. 



It is due mainly to Professor Abbe, of Jena, that, dur- 

 ing the past twenty years, a real science of "microscopj^" 

 has come into existence, the aim of which is to develop 

 the theory of the objective and to enlarge its hitherto 

 limited powers. In fact the jaractical application which 

 he has made of the laws of diffraction is the basis of by 

 far the greater part of all the advance which has recently 

 been made in the use of the microscope for scientific pur- 

 poses. His investigations have not only resulted in the 

 production of lenses of unequalled delicacy and perfec- 

 tion but have imparted a new interest to the study of 

 purely theoretical ojitics and have given rise to a large 

 and growing literature of the subject. The increased 

 importance thus conferred on this phase of the matter, 

 together with the rapid broadening of the field of re- 

 search, has led to a desirable separation between the study 

 of the microscope as an instrument, and the study of the 

 results of its employment. 



