BULLETIN 



OF THE 



TORREY BOTANICAL CLUB 



Vol. XVI.] New York, August 1, 1889. [No. 8. 



On aFossil Marine Diatomaceous Deposit from Atlantic City, N. Jb— IL 



By C. Henry Kain and E. A. Sciiultze. 



Plates XCII. andXCIII. 



(Continued from page 76.) 



Since the publication of the first paper upon this deposit, the 

 well from which the specimens were obtained has been sunk to a 

 depth of over 1200 feet, so that the range of the diatomaceous 

 strata can now be pretty well determined. The richest portions 

 are at the depths, respectively, of 406,550 and 625 feet. While 

 all the strata contain many species in common, yet the stratum 

 at 406 feet appears to be essentially different from the others in 

 regard to the size and general character of species. At a depth 

 of 625 feet a stratum about four feet m thickness occurs, in which 

 the predominant forms are identical with those found at 550 feet. 

 Below this, only a few scattered diatoms are found, until a depth 

 of 6yy feet is reached, when they disappear entirely. ~ As these 

 beds begin at a depth of 387 feet, it will therefore be seen that, 

 mcluding the sand beds which separate them, the series occupies 

 a thickness of about 290 feet. It is interesting to note that, 

 throughout the entire deposit, iron pyrites in minute crystals is 

 abundant, and when specimens of the dry earth are placed under 

 e microscope, the glittering crystals of pyrites are often very 

 beautiful. Microscopists probably remember how great an inter- 

 est was excited, a few years ago, by the announcement that 

 diatoms had been discovered in the London clay, so coated with 

 pyrites as to appear gold-plated. The circumstance was consid- 

 ered rather remarkable. In this deposit, the mineral appears in 

 crystals rather than in the form of a smooth coating, and doubt- 

 less the partial disintegration of the valves that is sometimes no- 

 ticed is due to the chemical action of the pyrites. 



In addition to the list of species previously published, the fol- 



th 



lowing have been observed : 



