MR. AGASSIZ'S LECTURE.

Mr. Alexander Agassiz delivered a very interesting lecture in Sanders Theatre last evening on the results of his recent investigations of coral growths about the Fiji Islands. Mr. Agassiz took as his subject, "The Present State of the Theories of the Formation of Coral Reefs," and said in part: The theory of Darwin was that the formation of attols or coral barrier reefs was due to the subsidence of the district where they are situated. Dana's observations seemed greatly to strengthen the theory and its very simplicity gained it popularity. The first tangible objection to the theory was found in 1881 when a coral reef twenty-five fathoms deep was discovered off Yucatan, a peninsular which is still rising. My theory is that under the proper favorable conditions coral formation will start wherever a sub-station exists at a suitable depth beneath the surface of the water.

The sub-stratum about the Fijis is generally limestone and the height at which the coral formation begins, generally about forty feet below the surface, may have been reached by a gradual upward growth of the substratum, as well as by subsidence from a higher altitude. In either case the present theory is that it is an independent growth. However, more than anything else the results of my trip have been to make me realize that the whole theory of coral formation is still very uncertain. A few interesting discoveries about the Fijis have shown that the very old theory that atolls are coral growths on the rims of sunken extinct craters, for which Darwin and Dana expressed great contempt, was not entirely groundless but in some cases perfectly true.