1899] MICROSCOPICAL JOURNAL. 53 



In fact, the marl is fresh-water and became brackish by 

 evaporation. All natural water contains some solid in- 

 gredients, — chloride of sodium, and also some silica, or 

 oxide of silicon. Now let us see what Ehrenberg the 

 earliest observer found in the marls of the Great Plan • 

 In the report of the geological explorationof the fortieth 

 parallel, Vol. 1, p. 120, Clarence King says : "Specimens 

 of the white strata were subjected to microscopic analysis 

 by Dr. C. G. Ehrenberg of Berlin, who found forty-six 

 distinct species oi' diatoms. Of these, 28 have been classed 

 as Polygastera and 18 of Phytolitharia, the most abund- 

 ant species being Gaillionella granulata, G. sculpta and 

 Spongiolithis acicularis. In -a lavender colored bed far 

 up in the series above the acidic tuffs, further sundry 

 beds are observed in the same sections containing more 

 or less infusoria, in which the following were found by 



Mr. Charles E. Wright : Gaillionella ? Spongiolithis 



acicularis, Pinnularia inaequalis, Coscinodiscus radiatus. 

 G. granulata is Melosira granulata and indistinguisha- 

 ble from M. distans as is G. sculpta. P. inasqualis is 

 Cymbella lanceolatum. C. radiatus is the last and evi- 

 dently the round end of M. distans. S. acicularis is 

 the sponge spicule I have found and comes from Spongia 

 rluviatilis. In this way, Y/right's and Ehrenberg's speci- 

 mens agree with mine. This shows that the Occidental 

 Sea covered also a part of Kansas east of the Rocky 

 Mountains and makes of it a vast sea. Later I shall dis- 

 cuss the facts in California. I have lately received speci- 

 mens from the Arizona bed of that sea. They were sent 

 by Professor W. P. Blake, director of the School of 

 Mines, Tucson, Arizona. 



Diatomaceous Earth from Arizona Containing Cyclotella. 



BY A. M. EDWARDS, M. D. 



I have recieved from Prof. Wm. Blake, Director of the 

 School of Mines, of the University of Arizona at Tucson, 



