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POPULAR SCIENCE MONTHLY. 



hill country and the fertile valleys that 

 send their waters to the river Beni. On 

 the other side lay a high plateau, at a 

 uniform altitude of from twelve thou- 

 sand to thirteen thousand feet, from 

 which the tops of low rocky hills here 

 and there emerged. This plateau had 

 obviously been at one time submerged; 

 evidence was plentiful that in ancient 

 times the glaciers enveloped a large part 

 of the slopes that led down to it from 

 the main Cordilleras and reached down 

 many miles farther than now. In the 

 immense pile of debris left by the gla- 

 ciers deep valleys were afterward cut by 

 the action of water, and into these val- 

 leys the glaciers of a second period of 

 advance protruded their snouts, depos- 

 iting moraines that could still be traced 

 in situ as much as four or five miles 

 below the present limit of the ice. Con- 

 trary to the apparently general impres- 

 sion that the peaks of the Cordilleras 

 were volcanic, the author had not been 

 able to find any trace of volcanic action 

 along the axis of the range. The Cor- 

 dillera Real had been elevated by a 

 great earth movement, and the heart of 

 the range consisted of granites, schists 

 and similar rocks. The whole range 

 might be described as highly mineral- 

 ized. Gold was found at several points, 

 but the chief auriferous valleys were 

 those on the east side of the range. 

 Just below the snowy mass of Cacaaca 

 on the west was a really enormous vein 

 of tin; and antimony, cobalt and plati- 

 num have been found in different parts. 

 The great copper deposits were not in 

 this range, but farther west. The flora 

 of the high regions of the Cordillera 

 Real was apparently sparse, but is prob- 

 ably more abundant in the rainy season. 

 Bird life was more prolific and birds 

 were numerous, at suitable places, up to 

 an altitude of seventeen thousand feet 

 above the sea. 



ZOOLOGY. 



The most recent elementary text- 

 book in zoology is from the press of 

 The Macmillan Co. Professor and Mrs. 

 Charles B. Davenport are the joint 



authors. It is recognized now-a-days 

 that what the general high school or 

 elementary student in zoology needs is 

 not professional training in that sub- 

 ject, but rather an opportunity to view 

 the field so that he may have as wide 

 an acquaintance as may be of the forms 

 of animals and of their doings. This 

 he needs that he may have an interest 

 in the things of nature and that he 

 may be a more intelligent member of 

 society in the things pertaining to his 

 welfare as affected by animals. The 

 book is therefore an attempt to restore 

 the old natural history in a newer garb. 

 The text is divided into twenty-one 

 chapters. The first of these deals with 

 'The Grasshopper and its Allies,' fol- 

 lowed by others upon the butterfly, 

 beetle, fly, spider, etc., similarly treated. 

 Each chapter has one or two 'keys' — ■ 

 that is, arrangements whereby the 

 families of animals may be determined. 

 The book is richly illustrated by means 

 of half-tone and line reproduction: a 

 number of photographs are from life, 

 and one of these is a flash-light photo- 

 graph of a slug and an earthworm 

 crawling upon a pavement at night! 

 Outlines for simple laboratory work 

 and a list of books dealing with the 

 classification and habits of American 

 animals are to be found in an appendix. 

 Many good things might be said of this 

 contribution to zoological text-books. 

 This ought to be said, that it will be a 

 book which will be of value to any 

 person who, while upon his holiday 

 trip, wishes to learn about the animals 

 he may come across. 



ORNITHOLOGY. 

 Mr. Chapman is equally at home 

 with camera or pen. In 'Bird Studies 

 with a Camera, with Introductory 

 Chapters on the Outfit and Methods of 

 the Bird Photographer,' he gives us 

 some of his many experiences from 

 Central Park to the swamps of Florida 

 and the bare rocks of the Gulf of St. 

 Lawrence. The first two chapters are 

 devoted to a brief discussion of the 

 outfit and methods of the bird photog- 



