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THE POPULAR SCIENCE MONTELY. 



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 re- 

 quiring the minutest accuracy, and so satu- 

 rate his mind with the conception of exact- 

 ness 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 con- 

 clusions, 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 im- 

 bued him. There are immense advantages 

 which the science may claim as an educa- 

 tional instrument. In its power of cultivat- 

 ing 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 distri- 

 bution and migrations of peoples. 



Transitions of Fanna 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 Mis- 

 sissippi 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 character- 

 istic 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 tran- 

 sitions 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 Flay- 

 fair, 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 peo- 

 ple. 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, modi- 

 fying their climate and forming a junction 

 between three continents. The Atlas range 

 is a mere continuation of the south of Eu- 

 rope. 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 essen- 

 tially 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 Sa- 

 hara. 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- 



