find a shell in it, you put the shell over here, and if you find a bone in it, you put the bone over here.” You’re talking about a little, infinitesimal scrap of bone or shell? It was from a mouse, from a shrew, so they were really small, and the shells were mostly snails, also tiny, tiny. You pushed this little bit of sand around and went through the whole thing until you got out all the organic material. I finished and brought my bowl back to him and I said, “Okay, I’m done. What do you want me to do now?” “Well go get some more.” He had a row of garbage cans lined up against the wall of the lab, full of the sediment. I spent the whole year sifting sand. The Geology Department at the university was also involved with producing a detailed map of the geology of the United States, and they were sending most of their grad students to Colorado to do field mapping. There was only one other woman in the program—her name was Karen—and everyone expected that our theses would involve working with the collection of fossils in the university’s museum. I said to Karen, “The guys are doing work out in the field. Why can’t we do that?” She said that was a good idea, so we went to the director and asked if we could go, too. The faculty was somewhat nonplused, but our proposition was accepted, and we went off to the foothills of the Sangre de Cristo Mountains. We had a tent. We had sleeping bags. We had a Coleman stove and a Coleman lantern and a .22. I figured if there were bears out there, a .22 would be a good thing to have. When the ranch foreman saw our gun he said, “Ladies, if you meet a bear he’s going to eat that thing like a lollipop!” So you and Karen were literally trailblazers. We were. I was a student just as the Women’s Movement was starting to gain momentum, but I was pretty much immersed in my work. I do remember that I was asked to pour the coffee at the department meetings, but there was no condescension involved. 50
To the grad students in the department, I was “one of the guys.” It’s interesting—I still get the bulletin from the school and many of the graduate students are women now. They’re out in Antarctica, in Tibet . . . they’re all over the place doing all kinds of stuff. Karen ended up getting her PhD in Colorado and she’s just recently retired as a state geologist in Montana.
that have been exposed by stream erosion in several places. The chasm across the stream from the old dam at the Deserted Village and the scenic overview from above Seeley’s Pond are impressive. And semiprecious pebbles of the mineral carnelian can be found in the Green Brook below Seeley’s Pond.
What kind of work did you do in Colorado?
Is there evidence that Blue Brook was ever more powerful, or did the quiet flow carve out the valley over thousands of years?
We were mapping and collecting fossils that would determine the age of the rocks. The whole concept of mapping was completely different then. Imagine doing any kind of mapping without aerial photography, without computers! All the lettering was done by hand. Five years after we were finished, the Geological Society of America produced a new geologic map of the United States and our work was included on it.
Stream flow can change dramatically in this region, especially by glacial blockage or tilting of the earth under the weight of the ice. Blue Brook, the main stream through the park, was the outlet for Lake Passaic—a glacial lake once thirty miles long, ten miles wide, and two hundred feet deep that filled the area that is now the Great Swamp. The stream carved its valley beginning with the last ice age 25,000 years ago.
How did you end up on the East Coast?
What are the geological connections between the Great Swamp, the Passaic River, and the Watchung Reservation?
I grew up in New York City, in the Bronx, and I went back to New York after I finished my degree. I taught high school in New York. Then when I got married, we moved to New Jersey and I taught geology at Rutgers. That was nice because I got to do a lot of fieldwork with the students. What makes the Watchung Mountains unique compared to other landscapes on the East Coast? The geologic history of the East Coast is long, and in many areas highly complex. The generations of movements of the continents have produced many different combinations of rock types and structures. There are Triassic fault basins similar to the one in New Jersey all up and down the East Coast. On the other hand, the rock types in New England are totally different, considerably older and far more complex. Are there points of interest in the Watchungs that were too far off the route to include on the Geology Trail but are worth visiting? There are interesting structures called “pillow lavas”
All were affected by the great continental glaciations. A million years ago, climate changes caused vast sheets of ice—up to a mile thick—to form in Canada and move slowly south, profoundly altering the landscape. The forward motion of the ice scoured and planed the rocks it passed over, and the ice terminus blocked many existing streams and rivers, causing them to change their drainage patterns. As the ice melted away, large piles and banks of rocks and debris bulldozed up by the glaciers further altered drainage and uncovered new outlets for the huge glacial lakes to drain. The Great Swamp is the soggy remains of the glacial Lake Passaic. As the ice retreated, spillways for this tremendous volume of water were created. As the ice retreated still further, the Passaic River resumed its northern flow, much of it now blocked by 250 feet of glacial debris. It follows a wandering path of least resistance through the remains of the lake bottom.
Do you have any favorite geological spots in the New Jersey or New York region? With a basic knowledge of geology, any road trip is interesting! There are Cape May diamonds on the broad beaches of the southern coast. Remains of huge glacial lakes that occupied much of northern New Jersey. The Delaware Water Gap. The Highlands. The site of the first dinosaur discovery in the New World. A mine containing a suite of minerals found nowhere else in the world. Virtually every spot has some aspect of interest, whether it be rock type, history, or commercial use.
Ruth Canstein Yablonsky is Park Naturalist at the Trailside Nature & Science Center at the Watchung Reservation, where she has been teaching children about the natural world for almost three decades. Yablonsky grew up in the Bronx, attended Hunter College, and earned a master’s degree in geology from the University of Michigan. In 2009, she won the Patricia R. Kane Lifetime Achievement Award for excellence in environmental education from the Alliance for New Jersey Environmental Education. 51
