|As a fossil collector living in the northeast United States, I quickly realized that good vertebrate fossil collecting localities are few. It seems that all the great vertebrate sites are found in western states. There are a few good sites in the east at places like Aurora, North Carolina, and Calvert Cliffs, Maryland, which have produced excellent fossils of Tertiary age. But they are too far away from where I live in southeastern Pennsylvania for a weekend "day trip."
I thought I'd have to make plans for a long trip out West to satisfy my interest for Cretaceous-era fossil vertebrates -that is, until I saw a field trip announcement in my local paleontology club's newsletter. The club was planning an outing to collect Cretaceous-vintage vertebrate fossils from Big Brook, New Jersey. The best part of this trip would be that the drive to the collecting site would take only an hour from the Philadelphia area!
I called Louise Schwartz, the field trip leader, to get directions to the collecting site. Louise asked me what I thought was a peculiar question: "Do you have any waders?" Waders? I thought to myself, what kind of place is this? I've been collecting for 15-plus years and have never needed waders. I've needed high boots at many places where I've collected fossils and minerals, but never waders! As I pondered why I would need them, Louise explained that Big Brook, the stream for which the site is named, runs through the Cretaceous sediments, and fossils wash out and are found in the streambed. She said the water is usually about one to two feet deep, with some places where it's up to four feet deep, but that we could get away with high boots. It was still mid-October, and the water wasn't supposed to be too cold yet. She told me that many people might just wear old sneakers. I asked Louise what she would be wearing. "Waders!" was her instant reply.
Louise said that Big Brook is one of her favorite places to collect fossils. "Where else can you find fossils [in perfect condition and] out of matrix?" she asked. She described Big Brook as "local, abundant, and accessible" and added that a variety of fossils are found here: shark teeth, snails, oysters, and belemnites (a hard part of an ancient squid) are common finds. Even human artifacts occasionally turn up. "I found two arrowheads there myself," said Schwartz. "The collecting is not strenuous and it is very relaxing."
Louise informed me that I'd need a shovel and screen, since the fossils are found when you screen the gravel from the streambed. In addition to these tools, I also packed an old five-gallon plastic bucket to carry all the fossils I expected to find - although I thought at the time that this might have been a little overly optimistic.
Then I picked up my fiancée, Annette Beale, who shares my interests in fossils, and we were off on our adventure to Big Brook. Big Brook is located near the picturesque town of Freehold. The historic Revolutionary War battlefield of Monmouth is close by. I had thought that all of New Jersey was just an extension of the concrete canyons of New York City, but most of the state is actually rural and very beautiful. New Jersey really lives up to its nickname of the Garden State.
In fact, we really didn't realize just how rural this part of New Jersey was. We thought that after getting off the New Jersey Turnpike we'd stop off at some fast-food restaurant so that we could recharge our batteries and freshen up before we got to the collecting site. We didn't know it at the time, but after we exited the turnpike there wouldn't be anyplace to stop. The closer we got to the site, the more rural the countryside seemed to become.
We pulled into the parking area about half-hour before the prescribed meeting time. We got our equipment out and suited up, ready for a day of collecting. We waited for the rest of our group to arrive, but only one other club member had appeared at the appointed time. We watched for cars coming in either direction, hoping to recognize someone else from our club. After waiting another half-hour we decided we couldn't wait any longer. Annette and I were both eager to start collecting fossils. The other member of our club told us which trail to take to get to the brook. Annette and I decided to go down and start collecting. Near the bridge over Big Brook, the small trail headed downstream and ran parallel to the brook. The stream bank seemed too high to climb down at the bridge, so we walked down the trail to find the first easily accessible path to the brook.
After walking about a hundred yards down the trail, we were finally able to get into the brook easily. Big Brook was a particularly beautiful place at this time of year. The dark black-green glauconite Cretaceous sediments were contrasted against a blanket of fall leaves sporting hues of yellow, orange, gold, and red. I thought to myself that this is a most unlikely looking place to find fossils; it's hard to imagine that this area used to be open ocean inhabited by mosasaurs and sharks. The fossils are not really visible at first. I remembered that Louise told me the best place to look for them is in the gravel bars. Annette and I went to the first likely looking gravel bar and started to shovel some sediment into the screen. After shaking the screen in the water to remove the sand and smaller stones, we examined the contents for any fossils. In our first screen we found a perfect little golden brown belemnite. It turns out that belemnites are some of the most common fossils found in Big Brook.
This first fossil whetted our appetite for what we really were here for: vertebrate fossils. We continued to shovel and sift with renewed enthusiasm, and seemed to find belemnite after belemnite in each screen. Then, in the fifth screen I found the first shark tooth, an extinct species of crow shark. It was about one inch in size and in perfect condition. All of the serrations were visible. Its color was a pleasing hue of earthy brown. If it were not for the dark color and shape, it could be mistaken for a modern shark tooth. Its shape, however, was quite different from that of any living shark. Most modern teeth are long and triangle-shaped, while the tooth we found was short and hook-shaped. After finding the first tooth we continued our search, working upstream; we were told that the vertebrate fossils were more plentiful the farther you went upstream. We went hopping from gravel bar to gravel bar, completely losing track of the time. We found nearly one hundred shark teeth, along with several fish teeth and scores of belemnites. About 25 of the shark teeth were between one and one-and-a-half inches long. It was about this time that I remembered that I should have bought new boots; the last time I wore my old ones, they leaked terribly. I also found out that the water was indeed cold, even though it was only early October.
We were hoping to find a mosasaur tooth but none was captured in our screen that day. After we had our fill of collecting we went back downstream to get to our car. My boots, by now very wet on the inside, made a particularly peculiar sound as we walked back to the car. Annette and I both had a large plastic baggie full of fossils. My five gallon bucket looked decidedly empty, and for most of the day it ended up being something on which to sit rather than a container for carrying a large amount of fossils. On the way back I found out why waders would have been a better choice. There are parts of the streambed that are particularly slippery, especially near the deep holes. We were about halfway back to the car when my foot found the edge of one of those deep holes and I lost traction, as if I were walking on ice. Suddenly I caught myself with my hands but by then it was too late, as the hole was about as deep as my arms were long. Now I was wet from head to toe. Since I was already wet, there was no reason to avoid the deeper holes. We just chose the shortest and most direct path to the car.
On the way back, we found that some more of our club members had arrived and had been collecting for some time. We asked each person we came across, "Did you find anything?" The question usually brought the same response. They took out a small plastic bottle or bag and showed us their finds. Each plastic bag or bottle contained some nice shark teeth but none of the teeth were over two inches long. Every person we spoke to said that further downstream someone found a mosasaur tooth. One of our club's members had indeed found a mosasaur tooth, about an inch in length, in the same area that we had looked in and passed over. We had been sifting this area only about a half-hour before.
Fellow collector Ned Gilmore has hunted Big Brook fossils since 1984. He said that this area has revealed fossils since at least the turn of the century and that "the fossils are abundant." Big Brook cuts through the Upper Cretaceous Red Bank, Navesink, and Mount Laurel formations. Oysters, belemnites, and brachiopods are common invertebrate finds. He said that the best part about collecting in Big Brook is the abundance and variety of fossil vertebrates. The most common vertebrate fossils are the teeth of Squalicorax sp. (an extinct crow shark), Scaphanorhynchus texanus (a goblin shark), Cretolamna sp. (a mackeral shark), and Archaeolamna sp. (another mackeral shark).
Most of the shark teeth are about a half-inch long but some reach two inches in length. Gilmore said that dental plates from rays and fish teeth (including sawfish teeth) can also be found. He added that fossils from mosasaurs, plesiosaurs, and even dinosaurs have been collected here, but they are rare. "Another neat thing about Big Brook is that it has a Pleistocene fauna," said Gilmore. "Mammoths, giant beavers, and even giant ground sloths have all been found here. But you have to carefully examine the bones you find in Big Brook", noted Gilmore. "There is a lot of iron that can stain a modern bone so that it looks like a fossil."
I just hope that Big Brook and other sites like it stay open and accessible to amateur collectors. At present, there are no restrictions on collecting. Collecting should be limited to sifting the streambed. Since our first trip to Big Brook, Annette and I have been back several times. It was on one of these subsequent trips that we finally found a mosasaur tooth. It was about one and a half inches long and perfectly preserved. Each time, the collecting gets better - and of course I always remember to keep an extra set of dry clothes in the car. But I still have to buy some waders - or at least new boots!
Sourse: Lapidary Journal August 1995 (p. 67-68, 117- 119)