That same year he was hired by Yale President Timothy Dwight IV as a professor of chemistry and natural history.

Some time around 1818, Ephraim Lane took some samples of rocks he found at an area called Saganawamps, now a part of the Old Mine Park Archeological Site in Trumbull, to Silliman for identification.

[5] He played a major role in the discoveries of the first articulated fossil fishes found in the United States, which he discovered in Newark Supergroup deposits near Connecticut, and were later described as the genera Redfieldius and Semionotus.

His efforts convinced Frederick Barnard, later president of Columbia College, that women ought to be admitted as students.

"The elder Silliman, during the entire period of his distinguished career as a Professor of Chemistry, Geology and Mineralogy in Yale College, was accustomed every year to admit to his lecture-courses classes of young women from the schools of New Haven.

In that institution the undersigned had an opportunity to observe, as a student, the effect of the practice, similar to that which he afterward created for himself in Alabama, as a teacher.

[15] At 6:30 in the morning of December 14, 1807, a blazing fireball about two-thirds the apparent size of the Moon in the sky, was seen traveling southwards by early risers in Vermont and Massachusetts.

The largest and only unbroken stone, which weighed 36.5 pounds (16.5 kilograms), was found some days after Silliman and Kingsley had spent several fruitless hours hunting for it.

The owner, a Trumbull farmer named Elijah Seeley, was urged to present it to Yale by local people who had met the professors during their investigation, but he insisted on putting it up for sale.

His son Benjamin Silliman Jr., also a professor of chemistry at Yale, wrote a report that convinced investors to back George Bissell's seminal search for oil.