HOME - Front Page
General History / Geology 1 of 1


Michigan is easily recognized when looking at a map due to being shaped like a mitten. Bay County is located where the index finger and thumb of your hand meet.

Ice Age map of MichiganSaginaw Valley flood basins
- Top Left: Area of Michigan covered with ice (white) and water (blue).
- Top Right: Flood basins in Saginaw Valley.

Ice Age:

The [Ice Age] played a major role in sculpturing the land masses of Michigan and the surrounding Great Lakes. Scientist believe Ice Ages occur about every 150 million years and last only a few million years. Fortunately, our last Ice Age began about 2.5 million years ago and ended a mere 10,000 years ago. Such huge time periods makes it hard to fathom climate affects of nature versus those induced by man.

Natural effects:

The graphic on this page shows what Michigan was like about 50,000 years ago as the last Ice Age receded. In this geological depiction, the Saginaw Bay basin is still covered with ice bounded to it's southwest by a large body of water covering the central portion of Michigan. This large body of water has been called the Huronic Sea or Lake Warren by geologist. They also named what is Lake Michigan as [Lake Chicago]. The major geographic regions of Detroit, Chicago and the areas surrounding them was completely covered by water. A water channel stretched across the mid-section of Michigan connects the Saginaw Bay area to Lake Michigan. The natural forces of the Earth were favorable to Michigan leaving a land area rich in minerals and surrounded by great bodies of water including many inland lakes and rivers. The other graphic may surprise you as it shows substantial coal deposits that flow inward from the Saginaw Bay. Heavy deposits in dark gray, flow through the southern portion of Bay County then southward into other counties.

Map of coal deposits (light-gray) in Bay County and surrounding areas. Dark-gray represents heaviest deposits.


The Ice Age that helped to form the area of Saginaw Bay Area created a valley at the foot of the bay that is Bay County. It is essentially flat land that gradually slopes downwards towards the bay. This huge basin of initially sediment would evolve into marshland and eventually soil rich in nutrients that would be farmed. Rivers would traverse the land providing a ready source of water for the early stages vegetation. Animals of most species found in Michigan would find it a natural habit as did humans thousands of years later.

The shore lines of the Saginaw Bay are typically sandy with random areas of marshland. The size of the bay is such that all that can be seen from most shore lines is a body of vast fresh water giving the sense of being on at the edge of an ocean.
[-] Map of Great Lakes water system. Source: www.on.ec.gc.ca.com


The climate of the Saginaw Bay area is favorable. Some protection form fierce winter weather that comes from the north and northwest is provided by being on the eastern shore of Michigan. During the warm weather months, the bay provides a cooling effect to communities along it's shoreline with only the direction of the wind determine the degree of cooling. Bay County sits on the lowest plane and is somewhat more protected than the other bay communities to the North, East and South. However, storms coming from the northeast have result in some of the areas worse storms, especially in Winter months when snow storms can bring frigid temperatures and large snow falls.
[-] Map of Great Lakes average climate conditions. Source: www.on.ec.gc.ca.com

General History Menu
Native Settlers
Pioneer History
20th Century
Photo Gallary
Page Board
Educational Resource:

Environment Canada and the US EPA have a joint agreement in managing the resources of the Great Lakes. Their web site provides a very thorough understanding of the Great Lakes geological and ecological systems. Visit:
The Great Lakes - An Environmental Atlas and Resource Book.
Online Resources:

[-] Bedrock Formation
Source: Michigan DNR

History Tid-Bit
Birney Park was originally called Madison Avenue park, it was renamed in honor of Judge James Birney, one of the early pioneers of Bay City. {Learn More}

HISTORY: Bay City was originally known as "Lower Saginaw."