328 CARNEGIE INSTITUTION OF WASHINGTON. 



migrating school of fish which, following the sea-current southward, 

 had been swept into the inland basin where the Lompoc bed was form- 

 ing, perhaps assisted by a high tide and the inward movement of 

 surface-drift induced by a west wind; and that, being practically land- 

 locked, they had quickly succumbed to the effects of rapidly increasing 

 temperature and salinity — these changes being brought about by the 

 shallow nature of the basin. Herring are known to be extremely 

 sensitive to these influences. The facts of the topography of the Lom- 

 poc area at the period represented by the above event were found to 

 agree with this interpretation, and it was also found to be in harmony 

 with conclusions arrived at by wholly different lines of research. 



A study and detailed report of the diatom flora of 24 samples of 

 calcareous sand, collected in the Bahamas and along the Florida Keys 

 as far west as Tortugas, were made at the request of the collector, 

 Dr. T. Wayland Vaughan, of the XJ. S. Geological Survey. About 150 

 species were found, including 13 new species, figures and descriptions 

 of which will be published at some future tune. The significant fact 

 brought out by this investigation was the evidence it afforded of the 

 retarding effect of calcareous waters on the growth and development 

 of diatoms. Not only was the number of species low in comparison 

 with similar gatherings made in non-calcareous waters, but many of 

 the individuals showed retarded development, in the imperfectly 

 silicified character of their ''skeletons" and in the frequency of mis- 

 shapen and grotesque forms. Certain facts not germane to this 

 report indicated that this retardation was probably due to an inade- 

 quate supply of silica in the waters of this locality, caused by the 

 replacement of quartz sand by calcareous sand, and perhaps also by 

 the further poverty of silica in the sea-water resulting from the for- 

 mation of the insoluble compound, calcium silicate. 



Some fresh-water samples were examined for diatoms and identifica- 

 tions were made for Dr. N. Gist Gee of Soochow, China. 



A veiy interesting study was made of some Uving diatoms contained 

 in atmospheric dust, brought down by a snowstorm at Madison, Wis- 

 consin, and sent by the collector. Professor A. N. Winchell, of the Uni- 

 versity of Wisconsin. Four species were found in this dust; and it is 

 interesting to note that two, Hantzschia amphioxys (E.) W. S., and 

 Navicula borealis (E.) K., seem to be frequently present in atmospheric 

 dust, both here and in Europe. Then- terrestrial home is in cool 

 sphagnum bogs and the moss on the shady side of tree-trunks. 



Some diatoms of great interest were secured in material dredged 

 at Pago Pago, Samoa, by Dr. Alfred G. Mayor. 



Passing over a considerable number of small investigations made 

 during the year for different parties, it may be well to refer here to an 

 informal report made to the U. S. Bureau of Fisheries on the diatom 

 flora of Woods Hole, Massachusetts. This report was based on studies 



