Brachiopods:
* Spiriferids: Among the most common brachiopods, these had a characteristically "spiry" shell with prominent ridges.
* Atrypids: These possessed a smooth, rounded shell, often with fine ornamentation.
* Strophomenids: This group had a distinctive flattened shell, often with a hinge line that extended beyond the width of the shell.
Mollusks:
* Ammonoids: These extinct relatives of modern squid and octopus possessed coiled, chambered shells, often with complex sutures.
* Nautiloids: Similar to ammonoids but with simpler sutures and often a straight or gently curved shell.
* Bivalves: This group, including clams and oysters, continued to diversify in the Devonian, displaying a wide range of shell shapes and sizes.
* Gastropods: Snails and their relatives were present in the Devonian, leaving behind a variety of spiral shells.
Other Shelled Organisms:
* Trilobites: Although declining in diversity, trilobites still possessed their distinctive, segmented exoskeletons.
* Crinoids: These stalked echinoderms, commonly known as "sea lilies," had a cup-shaped shell (the calyx) at the base.
* Bryozoans: These tiny colonial animals formed complex, branching structures with individual, box-like shells called zooids.
Important Note: The specific types of shells found in Devonian rocks vary greatly depending on location and the particular time period within the Devonian.
If you have a specific locality in mind, it would be helpful to provide more details so I can give you a more accurate and detailed list.
