GEOLOGY. 305 



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plan of growth to have a very subordinate value, he did not hesitate 

 to express his belief in its affinities to Nummiditia. Mr. Sterry 

 Hunt also stated that the mineral silicates, occurring in the chambers, 

 cells, and canals left vacant by the disappearance of the animal matter 

 of the Eozoitn, and in many cases even in the tubuli, filling up their 

 smallest ramifications, are a white pyroxene, a pale green serpentine, 

 and a dark green alumino-magnesian mineral, which he referred to 

 Loganite. The calcareous septa in the last case are dolomitic, but 

 in the other instances are composed of nearly pure carbonate of lime. 

 Mr. Hunt then showed that the various silicates already mentioned 

 were directly deposited in waters in the midst of which the Eozodn 

 was still growing or had only recently perished, and that they pene- 

 trated, enclosed, and preserved the structure of the organisms pre- 

 cisely as carbonate of lime might have done ; and he cites these and 

 other facts in support of his opinion that these silicated minerals were 

 formed, not by subsequent metamorphism in deeply buried sediments, 

 but by reactions going on at the earth's surface. 



FISH THROWN UP FROM ARTESIAN WELLS. 



The statement has been frequently made of late years that with the 

 water thrown up from many of the artesian wells, recently bored by 

 the French in the northern district of the Sahara desert, small fish have 

 been ejected, from depths of 150 to 200 feet. This statement, which 

 has been generally discredited, is now, however, proved to be true ; 

 M. Desor, the eminent Swiss naturalist, who has recently returned 

 from an exploration of the Northern Sahara, testifying to its authen- 

 ticity. He states in a recent letter, that he " found the fish in the 

 stream leading from one of the wells, at the oasis Ain-Tala, where the 

 fish were observed when the water first rose to the surface. It is im- 

 possible that these fish should come from any where else than from 

 out of the well, for the water stands in no communication with either 

 basin or river. The fish belong to the family of carps, and if I am 

 not mistaken, to the proper species of Cyprinodon. The most curious 

 thing is that these fish , although coming from the interior of the earth, 

 from a depth of more than 150 feet, have nothing sickly or misshapen 

 about them ; they are of a most remarkable liveliness, and, what is 

 especially worthy of note, have fine, large, completely healthy eyes. 

 You know that the fish and other aquatic animals which are found in 

 the subterranean ponds of the Adelsberg Cavern in Steyermark, and 

 in the Mammoth Cavern in Kentucky, are all blind. Their ocular 

 organs are stunted, and often nothing is left of the eye but the optic 

 nerve. Some naturalists therefore, have tried to classify them as a 

 species of their own, while others maintain that every organ deprived 

 of the opportunity to exercise its functions must necessarily degen- 

 erate at last, and become defective. But here we have a fish from 

 the intenor of the earth, with perfect eyes. How are we to account 

 for this ? I confess that this phenomenon puzzles me, yet I think I 

 have found the key to the riddle. The subterranean basin, which 

 feeds the artesian wells, must be of considerable dimensions, as the 

 water springs up on a space of many square miles, wherever it is 

 bored. Besides these artificial wells, there are ponds in several oases, 

 especially that of Urlana, fed by rich sources, and from which real 

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