<p>The boulder appears to be dark grey  fossiliferous limestone or dolostone with softer tan layers which might be: limestone or calcareous claystone/siltstone/sandstone.
From the photo, the tan layers do not appear to be shale.</p>

<p>I have a hand specimen which is very similar from southern New Jersey.
It is harder grey limestone inter-layered with light tan calcareous siltstone.
<a href="https://i.sstatic.net/8YUOj.jpg" rel="nofollow noreferrer"><img src="https://i.sstatic.net/8YUOj.jpg" alt="enter image description here"></a></p>

CC BY-SA 3.0
2017-09-05T13:31:40.500Z
2017-09-05T13:31:40.500Z
Earth Science Expatriate
<p>I spotted this large striped rock found on Delaware River. Note the fossil in the first picture. What kind of rock is this?</p>

<p><a href="https://i.sstatic.net/3rgoj.jpg" rel="noreferrer"><img src="https://i.sstatic.net/3rgoj.jpg" alt="enter image description here"></a><a href="https://i.sstatic.net/0JcA8.jpg" rel="noreferrer"><img src="https://i.sstatic.net/0JcA8.jpg" alt="enter image description here"></a><a href="https://i.sstatic.net/7dYD7.jpg" rel="noreferrer"><img src="https://i.sstatic.net/7dYD7.jpg" alt="enter image description here"></a> <a href="https://i.sstatic.net/jMeNR.jpg" rel="noreferrer"><img src="https://i.sstatic.net/jMeNR.jpg" alt="enter image description here"></a></p>

CC BY-SA 3.0
2017-09-04T06:51:11.453Z
Use this guide to improve your question: https://earthscience.meta.stackexchange.com/questions/124/a-guide-for-asking-identify-this-rock-questions/125#125
Communisty
<geology><rivers>
What is the rock I found on the Delaware river yesterday?
fkltman
# What is the rock I found on the Delaware river yesterday?

(Asked by: username_0 on 2017-09-02)

I spotted this large striped rock found on Delaware River. Note the fossil in the first picture. What kind of rock is this?

[![enter image description here](https://i.sstatic.net/3rgoj.jpg)](https://i.sstatic.net/3rgoj.jpg)[![enter image description here](https://i.sstatic.net/0JcA8.jpg)](https://i.sstatic.net/0JcA8.jpg)[![enter image description here](https://i.sstatic.net/7dYD7.jpg)](https://i.sstatic.net/7dYD7.jpg) [![enter image description here](https://i.sstatic.net/jMeNR.jpg)](https://i.sstatic.net/jMeNR.jpg)

**Tags:** geology, rivers

> **Comments:**
> **username_1**: Use this guide to improve your question: https://earthscience.meta.stackexchange.com/questions/124/a-guide-for-asking-identify-this-rock-questions/125#125  

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## 1 answers

### Answer by username_2 on 2017-09-05. Score: 3

The boulder appears to be dark grey fossiliferous limestone or dolostone with softer tan layers which might be: limestone or calcareous claystone/siltstone/sandstone.
From the photo, the tan layers do not appear to be shale.

I have a hand specimen which is very similar from southern New Jersey.
It is harder grey limestone inter-layered with light tan calcareous siltstone.
[![enter image description here](https://i.sstatic.net/8YUOj.jpg)](https://i.sstatic.net/8YUOj.jpg)


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