l893-J NEW-YORK MICROSCOPICAL SOCIETY. 73 



providing such members as are interested in diatomology with 

 the means of verifying my own study of the same. 



" As far back as the year 1878 my attention had been called to 

 the statement made by Prof. J. W. Bailey, in his microscopical 

 observations made in the year 1852, and recorded in the Smith- 

 sonian ' Contributions to Knowledge,' that he had detected evi- 

 dence of marine diatoms in an indurated clay found by him on 

 the shores of Hillsborough Bay, in the vicinity of Tampa, Florida, 

 but from which he had been unable to isolate the diatoms on ac- 

 count of the stony character of the material. Through the inter- 

 vening years I, from time to time, tried to secure specimens of the 

 material as noted by him, but such specimens as I secured failed 

 to corroborate the fact of diatom contents. 



" As a consequence, however, of faith in his statement, I per- 

 sisted in the hope, and my hopes were realized very recently, as 

 the casual outcome of finding a schooner discharging here a 

 cargo of Florida River pebble phosphates. Examining the com- 

 position of the pebble aggregations, I noted the recurrence of 

 flattened, water-worn, and rounded nodules of a clay-like sub- 

 stance, which I found could be easily split into thin layers in- 

 definitely. Applying a hand lens, the clay yielded its secret, as 

 each fractured surface showed innumerable diatomaceous bodies, 

 indicating its marine origin as well as fossil nature. 



" The interest in this find is emphasized, as it possibly throws 

 new light on a geological question — i.e., as to whether fossil 

 marine, diatomaceous strata of miocene age could be found on 

 the United States Gulf coast of the same character as those on 

 the Atlantic coast. While the generic assemblage of species 

 does not agree with the Maryland and Virginia miocene diato- 

 maceous clays, the geological horizon may be the same, as the 

 phosphate deposits of the Florida peninsula were laid down upon 

 eocene limestone strata. It is known that the valuable phos- 

 phate rock nodules and organic vertebrate remains are embedded 

 in a clay that must be removed by washing, and the presumption 

 is that the clay, whenever this is the case, is of the infusorial or 

 diatomaceous kind. 



" The clay material, as sent to the Society, maybe conveniently 

 studied in various ways. Split into thin layers and examined by 

 condensed light, analogy will suggest a resemblance to the dia- 



