POSTGLACIAL DEVELOPMENT OF CONNECTING EIVEES OF GREAT LAKES. 491 



ROCKWOOD DISTRIBUTARIES. 



West of the channel which terminates at Peabody Island (also called Sturgeon Bar Island 

 on some maps) and which connects northward with Brownstown Creek several small, shallow, 

 interlacing depressions run southward to Silver and Smith creeks and by their situation and 

 relations to the area marked by distributaries just north of them appear to have been short- ' 

 lived channels made by water coming from the north over the very low barrier which forms 

 the divide between them and Brownstown Creek. They must have been very short lived 

 because none of them are cut back to that stream; their heads all begin south of the divide 

 along its southern side. 



Farther west between these channels and Rockwood several troughs on the north side of 

 Silver Creek and Huron River indicate still more faintly developed lines of flow from the north, 

 but no such features appear west of Rockwood or south of Huron River, unless they lie in the 

 great swamp back of Point Mouille, which has not been examined. The swampy channel which 

 separates Peabody Island appears to extend south a little west of the shore to the swamp at 

 the mouth of Huron River, and another swampy depression a quarter of a mile west of this 

 extends over half a mile north. 



These faint Rockwood channels have a very important bearing on the early history of 

 Detroit River and of that part of the Lake Erie shore which formerly spanned it. (See p. 493.) 



DISTRIBUTARIES NEAR AMHERSTBLTRG. 



In some respects the most impressive of all the distributaries are those on the Canadian 

 side southeast of Amherstburg. They are strongly developed and are longer and deeper than 

 most others. One or two of them are drowned for long distances back from their mouths, 

 making long estuaries or dead-water bayous. One of the most remarkable opens abruptly 

 through the bank of the present river in the south edge of Amherstburg and may be called the 

 Amherstburg distributary. Its floor was about a foot above the surface of Detroit River 

 at the time of observation. At this point it is not over 200 feet wide, but its floor is wet and be- 

 comes a marsh within a quarter of a mile south. The Amherstburg distributary runs south- 

 southeast for about a mile and then turns almost directly south and follows a slightly winding 

 course to the shore of Lake Erie half a mile southeast of Bar Point, where it ends in a swamp 

 which runs along the shore for about a mile behind a low ridge of dunes. From a mile south of 

 Amherstburg the channel has a width of about 500 feet and carries from 6 inches to 4 feet of 

 water. 



At Elliott Point, about a mile south of Amherstburg, another small distributary runs 

 southeast. It has two headward branches, one opening near the north range light and the other 

 about 60 rods farther south. These two branches unite within about a quarter of a mile in a 

 channel that crosses the Amherstburg distributary and about 1J miles beyond unites with still 

 another channel. The Elliott Point distributary is somewhat smaller than the Amherstburg 

 channel and is not so deep. 



About a mile east of Bar Point a short distributary heads less than a mile from the lake 

 shore and enters the swamp behind the dune ridge. The general level of the ground is 5 to 6 

 feet above Lake Erie, and this short channel appears to have gathered its water from the flat 

 area around its head. 



The finest of the Canadian distributaries, however, lies about 1J miles east of Amherst- 

 burg and runs south to Lake Erie. The backwater in this channel, giving it the appearance 

 of an estuary, extends northeast of Amherstburg to a point about 5 miles from the lake, but 

 the distributary characters extend to about 1J miles north of the Michigan Central Railroad. 

 Two headward branches meet about one-quarter of a mile north of the tracks. 



This distributary had its headward opening at a level considerably above Detroit River. 

 Its upper part was active only during the early part of the flow over the ridge, but its lower 

 part probably received contributions from the. Amherstburg and Elliott Point channels for a 

 much longer time. The channel east of Amherstburg has a sufficient depth of water through- 



