TYPE SLIDE OF THE FAMOUS SANTA MONICA DIATOM FIND OF 1878

In the 19th century, few fossil diatomaceous finds ever excited greater interest than that from Santa Monica, CA.

One day in 1878 Thomas Woodward was walking on the beach south of Santa Monica, California, when he stumbled across an unusual rock. This turned out to be a new specimen containing a great variety of fossil diatoms and it soon became one of the most exciting finds of the 19th century.

Although initially no other parts of the source of this specimen were found, a few years later Mr F.H. Dunning of Battle Creek, MI figured out the original source of the specimen was much further south, at the foot of steep cliffs at Redondo Beach. This was an area difficult to get to and only visible at low tide. An unusual current was apparently responsible for washing up a portion of it up north near Santa Monica. It was often referred to as the Santa Monica Find but later also from Redondo Beach.

Kain, the maker of this rare slide, was a famous authority on American diatoms and a skilled mounter. He published a paper in 1897 listing some of the many species found in this deposit with references quoted that could assist with the identification of the over 200 different species found as of that date. But even as of that year, additional newly described diatoms from that deposit were still being reported. Over 110 different examples of the Santa Monica (Redondo Beach) diatoms are found on this slide.

Professor Kain died in 1909 aged 69. A large proportion of his extensive collection, representing the principal fossil deposits throughout the world as well as samples of extant diatoms he collected, were left to the Smithsonian in Washington. To read more about him, please see the terrific essay about Kain on Brian Stevenson's site.

Some of the most interesting diatoms on this slide are shown below, imaged with DIC and a 40X objective:

SELECTED REFERENCES:
Schultze, E.A. and Kain, C.H. The Santa Monica Diatomaceous Deposit with List of References to Figures of Species. J NY Microscopical Soc XIII pp77-86. 1897.
Stevenson, Brian: Charles Henry Kain, 1840-1909 on Historical Makers of Microscopes and Microscope Slides (microscopist.net) accessed 3/18/21.

Acknowledgements: The author is grateful to James Solliday, President of the Microscopical Society of Southern California for alerting him to the story and nature of the Santa Monica Diatoms and to Dr. Brian Stevenson for his article referenced above.