305 



In town of Groveland, numerous beds of ochre are collected around 

 the heads of Duck Creek, and are frequently over an area of half a 

 square mile. 



In Washtenaw county, bog ore has been found at several places in 

 town of Augusta, and considerable beds of red ochre in town of Sha- 

 ron. 



The ochres may serve a very good purpose as an ordinary red or yel- 

 low paint. This may be obtained in a cheap manner, thus : stir the 

 sand in water, then after allowing a few minutes for the siliceous 

 grains to settle, pour off the liquid and obtain the colored sediment 

 which is held in suspension. 



ANCIKNT LAKE RIDGE. 



At about twenty-five miles inland from the shore of Lake Erie, and 

 following a nearly parallel course to the lake and Detroit River, a low 

 gravelly ridge may be traced, corresponding in its character to that up- 

 on which the celebrated " ridge road " nms, along the southern shore of 

 Lake Ontario. Except where broken through by streams, this ridge is 

 very continuous, and ©f nearly uniform size ; so much so indeed, that I 

 have been able, without difficulty, to distinguish it from all ordinary un- 

 dulations of surface at whatever point it has met my observation, and 

 to trace its couree for jnore than sixty miles. 



The ridge has a breadth of several hundred feet, and rises with a gen- 

 tle curve into a somewhat conical form, to the average height of about 

 twelve or fifteen feet above the flat lands on the lake side. It is com- 

 posed of layers of coarse and fine gravel and beach sand, reposing up- 

 on the clays, which constitute the sub-soil of the contiguous country. 



From its resemblance to the beaches bounding the waters of the pre- 

 sent lake, as well as from the relative character of the country on either 

 side, no doubt remains in my mind that this ridge once constituted the 

 boundary of an immense expanse of water, which became afterwards 

 circumscribed to the dimensions of the present lakes. 



The ascent of the land on the lower or lake side, is much more grad- 

 ual and uniform than on the upper, and the "ridge" may be said to form 

 here a boundary to that belt of level country which bordei-s the Penin- 

 sula. This belt of land, as already described, is mostly clothed with a 

 dense growth of timber, and a dividing line drawn between this and the 



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