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THE POPULAR SCIENCE MONTHLY.

not firmly and securely based. The author did not infer that geology could find no place in the educational curriculum. There are many ways of neutralizing whatever there may be potentially hurtful in the use of geology for educational ends. One way to make a geologist is not to teach him any geology at all to begin with—to send him first into a laboratory, give him a good long spell of observations and measurements requiring the minutest accuracy, and so saturate his mind with the conception of exactness that nothing shall ever afterward drive it out. The uncertainties with which the road of the geologist is strewn have an immense educational value if we are on our guard against taking them for anything better than they really are. A man who is ever dealing with geological evidence and geological conclusions, and has learned to estimate these at their real value, will carry with him, when he comes to handle the complex problems of morals, politics, and religion, the wariness with which his geological experience has imbued him. There are immense advantages which the science may claim as an educational instrument. In its power of cultivating keenness of eye it is unrivaled, for it demands both microscopic accuracy and comprehensive vision. Its calls upon the chastened imagination are no less urgent, for imagination alone is competent to devise a scheme that shall link together the mass of isolated observations which field-work supplies; and its pursuit is inseparably bound up with a love of nature, and the healthy tone which that love brings alike to body and mind. Geology should be taught in schools also for its relation to geography and to the history of nations and the distribution and migrations of peoples.

 

Transitions of Fauna in the Mississippi Delta.—In a paper read in the American Association, in his absence, by W J McGee, Mr. L. C. Johnson said that he had made use of the Nita crevasse of 1890 of the Mississippi River to illustrate the manner in which the abrupt changes of fresh-water to salt-water fauna, and vice versa, of which frequent evidences appear in the delta, have been brought about. The crevasse was the most extensive that has been formed for many years; and through it flowed a volume of fresh water sufficient to transform the previously brackish lakes and saline bays on the left of the river into fresh-water lakes and estuaries. One of the prominent results of the flood was the destruction of the salt-water fauna and the substitution of a fresh-water and mud-loving fauna over an immense area. The oyster-beds along the coast, which were the basis of an important industry, were injured, and in many cases destroyed. The sea-fishing region was also ruined, and the pickerel and other characteristic fishes of the Mississippi may now be taken where four months ago only salt-water forms were found. Hitherto the geologist employed in the lower Mississippi region has been puzzled to account for the sudden transitions of fauna; but here we have a case where one of them was effected in a single week, over as wide an extent as all of those which have so embarrassed the student.

 

The Mediterranean.—The presidential address in the Geographical Section of the British Association, by Sir R. Lambert Playfair, was on the Mediterranean Sea. Its shores, the author said, include about three million square miles of the richest country on the earth's surface. They are a well-defined region of many parts, all intimately connected by geographical character, geology, flora, fauna, and the physiognomy of the people. To the general statement there are two exceptions—Palestine and the Sahara. The sea, a mere gulf, now bridged by steam, rather unites than separates the two shores, modifying their climate and forming a junction between three continents. The Atlas range is a mere continuation of the south of Europe. It is a long strip of mountain land, about two hundred miles broad, covered with splendid forests, fertile valleys, and in some places arid steppes, stretching eastward from the ocean which bears its name. In the east of the range the flora and fauna do not essentially differ from those of Italy; in the west they resemble those of Spain. Of the three thousand plants found in Algeria, the greater number are natives of southern Europe, and less than a hundred are peculiar to the Sahara. There are mammalia, fish, reptiles, and insects common to both sides of the sea. Some of the larger animals, such as the lion, panther, jackal, etc., have disappeared be-