OF ARTS AND SCIENCES. 263 



ill it ; and that the foundation on which they are built has 

 not, like that of the reefs described by Darwin and Dana, 

 been undergoing a process of subsidence or of elevation. He 

 further stated, that a free generation of coral animals detach 

 themselves from the parent stem, move through the water, 

 and select new situations, favorable for building, on the dead 

 corals. He exhibited a small mangrove-tree, and called at- 

 tention to its very long and numerous roots, by which it 

 strongly attaches itself to the coral sands, and thus confines 

 them. 



Mr. Desor made some remarks on the first appearance of 

 the Vertebrata in geological strata. From the absence of the 

 remains of Vertebrata in the Trenton limestone, which con- 

 tains the remains of a variety of invertebrate animals, and 

 also in two fossiliferous formations below the Bala limestone 

 in England, he argued that Invertebrata must have existed 

 long before the appearance of Vertebrata. Mr. Desor further 

 remarked, that, inasmuch as the remains of reptiles have been 

 found in the coal measures of Germany, fishes could not be 

 regarded as the only representatives of vertebrate animals in 

 the paleozoic series, unless we remove from this group the 

 carboniferous formations. 



Professor Agassiz stated, that he was satisfied, from an ex- 

 amination of the figures in Professor Burmeister's paper, that 

 the fossils found in the coal measures of Germany, and de- 

 scribed by him as the remains of reptiles, are the remains 

 of fishes. 



Mr. Whitney exhibited a specimen of iron, manufactured at 

 Springfield, out of ore brought from Lake Superior, which, he 

 stated, had been found on trial to possess uncommon strength. 



Mr. Alger exhibited a remarkable specimen of fossil Sigil- 

 laria from the sandstone of the coal formation of Nova Scotia. 

 It is fourteen inches in diameter, and three feet long ; the 

 lower part bulging out, as if approaching the lower portion of 

 the stock from which the roots proceeded. The flutings or 

 longitudinal furrows upon its exterior, of an inch in width, 



