8o 



SCIENCE. 



[Vol. X. No. 236 



orographic basin, resulting from the tilting of faulted beds. The 

 question of outlet is discussed in detail, the conclusion being that 

 the lake did not overflow. 



Chapter III. discusses the physiography of the Lahontan basin, 

 describing in detail the valleys and mountains, and its lakes, rivers, 

 and springs, and including numerous analyses of the waters from 

 these three sources. Attention is given to the peculiar playas or 

 broad mud-plains of the arid region of the Far West, as well as to 

 the temporary lakes, called ' playa-lakes,' which frequently flood 

 them. 



The physical histor}' of the ancient lake is fully and ably discussed 

 in Chapter IV. Under the head of ' Shore Phenomena ' we find 

 detailed descriptions and illustrations of the terraces, bars, embank- 

 ments, etc., that were formed about its shores. The highest of the 

 ancient water-lines is named the ' Lahontan Beach ; ' and the most 

 conspicuous terraces below this are the ' lithoid,' ' dendritic,' and 

 ' thinolitic' Each of these marks the upper limit of a variety of 

 tufa, from which it derives its name. 



Numerous sections are introduced to show the structure and rela- 

 tions of the mechanical sediments, which consist of two deposits of 

 lacustral marls, separated by a heavy layer of current-bedded 

 gravels ; thus recording two lake periods and an intermediate low- 

 water stage. 



Chapter V., on the chemical history of the lake, is especially im- 

 portant. It includes, first, a general account of the chemistry of 

 natural waters as they occur in streams, springs, lakes, oceans, and 

 enclosed lakes or seas, followed by descriptions of the tufas precipi- 

 tated from the water of Lake Lahontan, the salts precipitated when 

 complete evaporation took place, the efflorescences now forming on 

 the desiccated floor of the lake, and the salt-works of the region. 

 As already indicated, the tufas present three main divisions. The 

 lithoid tufa is a compact, stony variety, and is the oldest of the 

 principal calcareous deposits that sheathe the interior of the basin. 

 Thinolitic tufa is composed of crystals, and was formed in the an- 

 cient lake when it was greatly reduced by evaporation. The den- 

 dritic tufa has a branching or dendritic structure, whence its name, 

 and it is the newest of the tufa formations. 



Chapter VI. presents the life-history of the ancient lake as deter- 

 mined by the abundant moUuscan remains and other fossils that 

 have been found. The shells show that the lake was fresh through- 

 out its higher stages. During the period when thinolite was formed, 

 it seems to have been too concentrated to admit of the existence of 

 molluscan life, as no fossils have been found in that deposit. A 

 chipped implement discovered in the upper lacustral beds indicates 

 that man inhabited the Far West during the last rise of Lake 

 Lahontan. 



Chapter VII. is a brief resiuiie of the preceding chapters ; while 

 Chapter VIII. is devoted to a discussion of the quaternary climate 

 of the Great Basin, the periods of greatest lake-expansion being 

 correlated with the two glacial epochs of the Sierra Nevada, and 

 believed to indicate cold and moderately humid periods. 



In Chapter IX. we have a summary of the evidence bearing on 

 the determination of the geological age of the lake. The conclusion 

 reached is that it existed during the quaternary, but was more 

 recent than the date usually assigned for the close of the glacial 

 epoch. 



The tenth and concluding chapter contains an account of the 

 orographic movements that have affected the Lahontan basin since 

 the last high-water period, including a map showing all the post- 

 Lahontan faults, some of which are marked by exceedingly fresh 

 escarpments, and are evidently still in process of formation. 



The illustrations are profuse and admirably executed, and Mr. 

 Russell's style is throughout clear and graphic. Details are mainly 

 kept in the background, or presented in tabular form ; and it is 

 probable that both in general interest and educational value this 

 monograph is excelled by none of the publications of the Geological 

 Survey. 



Elements of Geodesy. By J. H. Gore. New York, Wiley. 8°. 



The present publication is a treatise on some geodetic operations, 

 and intended to give the beginner a clear insight into the subject. 

 It begins with a brief historical sketch of the various attempts to 

 determine the figure of the earth. The former half of the book is 



devoted to a description of the instruments and of the elementary 

 operations and methods of plane geodesy, but the principal object 

 of the author is to describe the methods of spheroidic and geoidic 

 geodesy. The student who begins to study this important branch 

 of geodesy will, or at least ought to, be conversant with the instru- 

 ments applied by geodesists, with the theory of least squares, and 

 with the calculation of triangulations, which are set forth at some 

 length in the first part of the book. On the other hand, the begin- 

 ner, who will find some valuable and practical hints in the chapters 

 on base measurements and the field-work of triangulations, will 

 miss a discussion of topographical methods and operations. The 

 book would become far more useful for the beginner, who must 

 study the simpler geodetic operations before beginning with the 

 measurement of the figure of the earth, if a description of the 

 methods and theories of topography were included in the plan. The 

 development of each formula is very complete, and the results are 

 given in the shape that the majority of writers have considered the 

 best. Examples are given to illustrate the application of the for- 

 mulas. The student will find at the end of each chapter a list of 

 books referring to the subject under discussion. F. B. 



NOTES AND NEWS. 



As we go to press we have obtained a copy of the opening re- 

 marks of Prof. S. P. Langley, president of the American Associa- 

 tion. Professor Langley spoke as follows : — 



Members of the Association, — While, for the main pur- 

 pose of our coming here, we are all of one mind, some must 

 remember a peculiar pleasure in their first attendance, when they 

 came to these meetings as solitary workers in some subject for 

 which they had met at home only indifference, and held themselves 

 alone in, till here, with a glad surprise, they met others, too, caring 

 for what they cared for, and found among strangers a truer fellow- 

 ship of spirit than their own familiar friends had afforded. With 

 such communities of purpose wherever two or three among us are 

 gathered together, it is a happy thing that we cannot remain stran- 

 gers ; for doubtless, of the many here who have habitually breathed 

 " the calm and still air of delightful studies," there are few but 

 know by experience how hard it is for one coal to keep alight alone, 

 and how especially good it is for the solitary workers to be brought 

 at times into the warmth of companionship. To a great many of 

 us, then, it may be counted as the very chiefest good of such an 

 assembly as ours to-day, that here each meets some one with a kin- 

 dred glow, and finds that interest and sympathy from his co-worker 

 without which the scientific life would be but too cold. It is most 

 fortunate, nevertheless, that our happy constitution as a body, not 

 only of investigators in science, but of teachers and lovers of 

 knowledge, brings those here in greatest numbers who disseminate 

 as well as produce it, and who are skilled to recognize the value of 

 the newly mined product when brought into this public exchange 

 of ideas. We must admit here, that foolish ideas as well as wise 

 ones are brought to this open mart, and that, in dealing with the 

 variety of papers now presented for acceptance, it becomes almost 

 as hard a task for us to shut out folly as to entertain wisdom ; for, 

 after all, who are we that judge, and how can we say " wisdom is in 

 us to decide," when it is chiefly because we are ignorant that we are 

 here ? Probably the only rule is that taught by experience, that since 

 art is long and life short, experience difficult and judgment uncertain, 

 knowledge commonly advances best by such little steps, that one 

 foot is not lifted till the other is securely planted on the solid ground 

 of fact. On the whole, then, while we agree that some rare visitors 

 have come to us over the " high priori road," do not let us welcome 

 without scrutiny all those who would walk over it into this associa- 

 tion's domain. At the same time, in view of our ignorance as to 

 the real nature and causes of things, I would plead with those of 

 you who are judges, for a large tolerance, even of what seem to be 

 errors of speculation, when these are found in company with evi- 

 dence of a faithful original study of facts ; for we shall then have, 

 at any rate, done our best not to turn away Truth, even if she has 

 come to us in an unfamiliar dress. And now I can only congratu- 

 late this assembly of her followers on a meeting which opens so 

 auspiciously, and express the hope, that whether in the new knowl- 

 edge which we may take to the section-room or find there, or in the 



