211 



while others had extended themselves into elongated 

 and forked points. This fungus does not form in the 

 tissues of the plants upon which it is parasitic, but is 

 merely an incrusting growth, spreading over and entirely 

 covering the surface of the stem and leaf. This compact 

 envelope is highly injurious to the infested plant, as it 

 prevents the access of air and light to its tissues. On 

 removing a portion from the pine leaves, the normal 

 green was found to have changed to a dull yellow, 

 similar to that of the decaying leaves. 



Dr. A. A. Hayes exhibited some specimens, resembling 

 Trachyte rock so closely, that most observers would 

 have mistaken them for Trachyte. 



The specimens consisted of hand specimens, having the uneven 

 fracture of trachyte, full of capillary passages, with some cavities ; 

 there were fractured planes of brown and flesh-colored minerals, 

 resembling feldspar, and some small red, brown-colored and black 

 granules ; but the most characteristic mark was the occurrence 

 of angular fragments and grains of yellowish green color, hardly 

 distinguishable from epidote by the eye. The external surface 

 was brown and uneven, like that of a weathered basalt, or trap. 

 The island from which these specimens came has been examined 

 by a geologist, and from the prevalence of this rock, it is said 

 that he pronounced the island to be of volcanic origin. A mass 

 was sent to Dr. Hayes, and he found it had structural planes, 

 the divisions producing trapezoidal masses, their surfaces and the 

 lines marked by darker colors, and, so far as could be determined, 

 there was evidence of the mass being part of a rock formation of 

 some extent. 



The chemical composition discloses the remarkable fact that 

 this rock is composed essentially of fish bones and altered shells, 

 which have passed through the alimentary canals of sea fowls. 

 Referring to communications before made, Dr. Hayes stated that 

 the organic matter of fish bones in the droppings of fowl, reacts 

 on the bone phosphate of lime, to eliminate acid salts of phos- 

 phoric acid, and these cement other portions, or decompose shells, 

 which are cornposed of carbonate of lime and animal tissues. 



