2010 - Year of the Niagara Escarpment

About the Escarpment

The Niagara Escarpment (or 'cuesta') refers to a limestone outcropping that appears in Wisconsin, Illinois, Ontario, Michigan, and New York, including the world-famous Niagara Falls. Here in Wisconsin this feature appears most prominently in Door County.

The Wisconsin legislature has designated 2010 as the 'Year of the Niagara Escarpment' in order to bring attention to this unique natural feature. A series of events is being planned by

This page is a celebration of this interesting remnant of the Silurian era.

Formation of the Escarpment

During the Silurian era, over 400 million years ago, much of what is now North America was a shallow, tropical sea. Over time, layers of sediment built up into a layer of limestone. This sediment included the calcium shells of the sea life of the time. Later, magnesium ions replaced some of the calcium, converting the limestone into dolomitic limestone (also called dolomite), which is harder than regular limestone.

Over time, this sediment layer hardened, and was shaped by the forces of the Earth as explained


The Wisconsin DNR has a list of state parks containing the NE:

Creatures of the Silurian

The Cambrian period is noted for the first appearance of a fossil record of life on earh. By the Silurian period, some 100 Million years later, evolution had produced a variety of new organisms.


Trilobites are arthropods, like today's spiders. They are probably more closely related to the present-day horseshoe crab, and 'pill bugs'. At least 19 species have been discoverd from the Silurian period. One of them, Calymene celebra, is the official State Fossil of Wisconsin.

A good book is Trilobites, by Riccardo Levi-Setti.It contains an atlas of fossils, with excellent photographs, arranged by taxonomy and geologicalperiod. Levi-Setti also discusses structure of the eyes, which he describes as "the first use of optics coupled with sensory perception in nature".


Cephaolopods ('head foot') first became prominent in the Ordovician. These organisms are the ancestors of today's octopus, squid, and nautilus. During the Silurian, many large cephalopods, up to 15 feet long, were dominent predators.