Reviews — Macfarlane's American Geological Railway Guide. 229 



geologist. Tlie forms assumed by skew sections of crystals, and 

 the relation of the cleavages to the faces in crystals of hornblende, 

 augite, and the allied species, being represented in large-sized 

 diagrams. 



The manner in which the constituent minerals of rocks vary in 

 deviations from the normal type is indicated in tables, and by fy 

 graphic method of considerable ingenuity. The weakest point of 

 the book is in its chemistry, which is somewhat unsystematic, though 

 such want of system may fairly represent the state of mind of many 

 mineralogists trained in the older systems of notation, and hesitating 

 between the many new ones. It would be well in this respect, for 

 the sake of uniformity, if geologists were to agree to adopt the same 

 standard system, preferably that of the new edition of Rammelsberg's 

 Mineralchemie. An example of eccentric etymology, on p. 101, 

 millemeter, is calculated to add new horrors to the metrical system, 

 and we trust that ere long the author may have an opportunity of 

 correcting it in a second edition. 



We had intended to go into more detail in our notice of this very 

 sterling work ; but as the price is exceedingly low, we think it better 

 to recommend our readers to become possessed of it, and study it 

 carefully for themselves. H. B. 



IV. — An American Geological Railway Guide, giving the 

 Geological Formation at every Eailway Station, with 

 Notes on the Interesting Places on the Routes, etc. By 

 James Macfarlane, Ph.D. (New York : D. Appleton & Co., 

 1879.) 



DR. MACFARLANE is already known to the readers of this 

 Magazine, by his work " The Coal Regions of America " (see 

 Geol. Mag. 1874, Decade II. Vol. I. p. 87). Further anxious to render 

 himself useful, he has published the above Geologists' Railway Guide, 

 which is both novel and instructive. The object of the author has 

 been to place in the hands of the traveller a series of geological time 

 tables indicating the formations which can be observed at the prin- 

 cipal stations on the railways at present constructed throughout the 

 States. Prefixed to each State is a list of the geological formations 

 occurring in it, and which subject is further expanded by about 

 fifty pages of prefatory matter, containing a general description of 

 the various geological formations of North America, with tables 

 showing their succession, and a geological sketch-map of the United 

 States. There are also foot-notes directing attention to interesting 

 geological places and objects on the routes of the railroads. 



Independently of his own geological knowledge and travelled 

 experience, Dr. Macfarlane has been considerably assisted in the 

 work by those geologists conversant with the different districts or 

 states which he has not personally visited. This assistance has 

 materially enhanced the value of the guide; and, while it is specially 

 intended for the use of American travellers, yet the prefatory 

 matter above referred to will afford much useful information to the 



