The rocks around Niagara Falls are primarily made of sedimentary rocks from the Silurian Period, around 443 to 419 million years ago. This period is characterized by a warm, shallow sea environment. So, you'd mainly find fossils of marine organisms that lived in this ancient sea.

Here are some examples:

* Brachiopods: These are ancient clam-like creatures with two shells. They were very common in the Silurian period, and their fossils are often found in the Niagara Escarpment rocks.

* Trilobites: These are extinct marine arthropods with segmented bodies. They are a hallmark of Paleozoic fossils, and their remains are also found in the Niagara region.

* Crinoids: These are sea lilies, which are filter-feeding echinoderms. Their fossils are often found in the form of detached "arms" or complete skeletons.

* Coral: While not as abundant as brachiopods or trilobites, some coral fossils can be found. These indicate a warm, tropical, shallow-water environment.

* Graptolites: These are extinct colonial animals that looked like tiny seaweed. Their fossils are often found in the form of thin, black "pencil-like" markings on the rocks.

You're unlikely to find dinosaur fossils around Niagara Falls, as dinosaurs evolved much later in the Mesozoic Era.

Keep in mind: Fossil hunting around Niagara Falls is best left to professionals and requires permits in many areas. It's important to respect the natural environment and avoid damaging any rocks or fossils.