Mussel distribution in relation to former stream confluence in Northern Michigan, U. S. A.

Schalie, H. van der

Publication Date: 1963

About this Item

It has been shown previously that certain Mississippi River naiades have invaded the St. Lawrence drainage system in the region of the Fox River and Green Bay on the western shore of Lake Michigan, Wisconsin, in post-glacial times when the Fox River was still joined to the Wisconsin River, a tributary of the Mississippi. The fluviatile species Alasmidonta marginata and Actinonaias carinata, for instance, now occur in 3 streams flowing into Green Bay, but not in the impounded waters of the Lake itself. The present discontinuous distribution of these mussels was explained by a former enlarged Fox River system with a dendritic river pattern that comprized these rivers during a low water stage of Lake Michigan. The southern species Alasmidonta marginata, Elliptio dilatatus and Lasmigona costata have been found in 3 northern Michigan rivers: the Millecoquin, in the eastern part of the Upper Peninsula, and the Carp and Ocqueoc, in the northern part of the Lower Peninsula. Again we have a discontinuous pattern of distribution. Particularly A. marginata is strictly fluviatile and the 2 other species also do not occur in Lake Michigan. Such an extension of their range from the northwest can be accounted for best by geomorphological evidence. Glacial geologists have indicated that a former Mackinac River occupied the bed of northern Lake Michigan during a post-glacial low water stage in Chippewa-Stan-ley times, approximately 8500 years ago. The rivers concerned, now tributaries of Lake Michigan and Lake Huron, must have been connected with the now submerged Mackinac River system before the higher lake levels separated them. An Atlantic species, Elliptio complanatus, has reached northern Michigan through other post-glacial confluences, for the east. It has also been found in the Ocqueoc River, although it is known to be absent from the Lower Peninsula, and in the Millecoquin of the Upper peninsula. 10 pp., 1 map, gr. 8.

Seller Inventory # W15979

Bibliographic Details

• Title: Mussel distribution in relation to former stream confluence in Northern Michigan, U. S. A.
• Publication Date: 1963