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Notice of the Peninsula of Michigan. 307 
servations of settlers and surveyors. These earths, I found 
almost uniformly to effervesce with acids, evincing much lime. 
They have quick sand fora basis, at various depths, accord- 
ing to the elevation of the ground. The pebbles and sand 
embraced in the soil are mostly siliceous, an small lumps of 
indurated marl sometimes intermingled. The earth on the 
surface rarely effervesces much with acids, the carbonate of 
lime having been taken up by plants, or decomposed by ve- 
getable acids. Oak openings are at first much less produc- 
tive than heavily timbered land where vegetable mould accu- 
mulates. On dry ground accessible to frequent fires, the 
, leaves, and annual plants are dissipated, eaiie 
‘soil; which is said to improve m much under cultivation— 
the roots and plants turned in, decay after the first season, 
and Sete brings to the surface, fertilizing calcare- 
ous earth. In the soil of oak openings, from 15 to 25 bus 
the acre of good wheat are procured, For this crop, lime is 
a valuable ingredient in the soil, which might be rendere 
much more productive by ploughing i in clover, fostered by 
gypsum. ‘This mineral can be procured at a small expense 
from the south-western part of Sandusky bay, where it has 
been recently discovered of superior quality, in great quanti- 
ty, and of easy access. It is compact, white, and embraces 
considerable gypseous alabaster. 
Rich fresh water shell marl, is of frequent occurrence in 
manne swamps; ponds, and wet basins that were formerly 
em various parts of the interior. Strata from two to 
e feet pas ceichaiocs are common in Oakland county, and are 
constituted almost exclusively of decayed shells. Good lim 
is calcined from this material in pits, with alternate layers o of 
in 
wood and marl. It may be advantageously u 
ture. Pipe and potters’ clay is found in Oaklandcou ounty. 
The soil of the hickory openings of the centre and western 
imp Be is much superior to that of the eastern oak region. 
e land is generally good from Oakland county to within 
foie miles of lake Michigan. 
The oak openings of the southern part of the peninsula are 
presented as superior to the northern division, the soil con- 
taining more 
Loose 
so ee energie rest in small baer on 
the surface in various parts of the interior, rarely more 
sufficient for the security of wells and cellars. They occur 
on the Chicago road. I noticed large bowlders of granite. 
