Delaware Beach Fossils, Who Knew?

[I_gotta_rock]

A few years ago, I found a fossilized something on the Beach at Cape Henlopen. It was embedded in quartz. It looked kinda like a belemnite, but the wrong material. I was told by Plax that it was much older than our cretaceous belemnites. I tucked it into a spot on the shelf and wondered about it. Since then I have seen a few posts here and there from folks in NJ finding nice little paleozoic pieces on their side of the bay as well.

 

This summer, I made it a mission to explore the Delaware beaches and see what I could find and how far north they went. I began at the cape and worked my way north, one beach to a trip.

 

Cape Henlopen's beach is rather lacking in pebbles this season, so not much to find, but I know they turn up! I have spotted them here and there in the intervening years.

 

The next few trips were Bowers Beach. Oh, yeah! Some are impressions of brachiopods and crinoids are so tiny in big pebbles that is just isn't worth it to take them home and wonder where on that pitted rock I found something recognizable. Others are very distinct chunks of coral replaced with chert, some with crystal quartz in the gaps between structural elements. Each time, I came home with a couple of fistfuls of nice little pieces, mostly about 1" across.

 

The next stop was the beach in Battery Park, in New Castle. This is not a nice bathing beach. It is on a heavily-industrialized section of the Delaware River. The beach is littered with slag, brick, glass and bits of other man-made "rock." But, the black slag definitely allows the brown chert to stand out more. Bingo! The prettiest horn coral I've found yet, plus a few other nice goodies. All told, I came home with about as much as I usually find at Bowers, but cutting my travel time from over an hour to just 20 minutes. *Insert Happy Dance Here!*

 

The last stop was a rare little stretch of river bank in Claymont, a mile or so from the northern border. The stretch was pretty narrow and short. There were plenty of pebbles, but not much chert. Nothing distinctly fossilized. Oh, yeah, and on the way BACK, I found, facing into the woods and hidden by the vegetation, a "No Trespassing" sign. Now they tell me. Ah, well, now I know it isn't worth the trouble anyway.

 

The Delaware Geological Survey, as far as I can find, has no public record of fossils at the beach. They note the Cretaceous at the C&D Canal, the Miocene in a farm field that got bulldozed for a highway, Pleistocene silicified wood in the fields and streams just south of the canal, and plant impressions from the canal down to the southern border. The corals and other marine impressions in the chert are Paleozoic, possibly Devonian or Silurian, but no one seems quite sure. They were part of the ancient sea bed when the Cretaceous stuff at the canal was still alive and can be found in the pebbles there, too, occasionally. I find it really neat and kind of surreal to think about all those fossils that were ancient when my ancient sea shells were still alive.

 

[Miocene_Mason]

15 minutes ago, I_gotta_rock said:

The next stop was the beach in Battery Park, in New Castle. This is not a nice bathing beach. It is on a heavily-industrialized section of the Delaware River. The beach is littered with slag, brick, glass and bits of other man-made "rock." But, the black slag definitely allows the brown chert to stand out more. Bingo! The prettiest horn coral I've found yet, plus a few other nice goodies. All told, I came home with about as much as I usually find at Bowers, but cutting my travel time from over an hour to just 20 minutes. **

 Nice report on a little known field, thanks for sharing! Now I gotta keep my eye out when I'm at Delaware beachs.

[Kimi64]

Nice photographs & hello from Maryland!

[ynot]

Sounds like a wonderful sojourn!

Nice pebbles and pictures.

Thanks for sharing.

[Plax]

Sounds like you are an intense researcher! Perhaps you can find the Merchantville Formation outlier in Claymont. Always wanted to look for it myself when I was living up north but never got around to it.

  You must have used a gallon of bug spray collecting at Bowers Beach in the summer!

[Richard Pearlstein]

So it is 5 years since your post, but I just today saw it and joined the forum.  Not sure if you are still online but wanted to ask.  Have you identified any of the fossils in your photos?   
 

I live in north Delaware (Glasgow) and have found similar fossils in my neighborhood.  I have found them in the riverbed by my house, and many areas where roadwork or utility work exposed underlying rock.  Also found many fossils in dark, finer grained silica nodules.  My area is confusing since it is a transition area between several geological formations, from iron hill with its gabbro to young and old sediment beds.  So I’m not sure where some of these belong.   The published literature seems to just focus on a narrow area both in time and locale.  
 

 

I will post photos of my finds in the future.