316 GEOLOGY OP EASTERN WISCONSIN. 



cept some new or doubtful species, may be found in tlie table of fossils 

 of the Trenton period. 



Industrial value. This formation makes two notable contributions 

 to the soil derived from it, either directly, or through tlie medium of 

 the drift. The one arises from the clayey members of the formation, 

 and furnishes an argillaceous constituent to the soil. They usually 

 contain, also, some lime, which, with the interstratiiied limestone, adds 

 a calcareous ingredient. The other has its origin in the arenaceous 

 shales, which give rise to a somewhat sandy soil. The two mingle 

 for the most part, producing an intermediate and excellent soil. In 

 portions of the towns of Ottawa, Eagle, Palmyra, and La Grange, 

 however, the sandy element is objectionably prevalent. 



The decomposing shales are used in the manufacture of brick, of 

 which they make an excellent quality. Some of the clays of this 

 formation possess an exceptionally fine textui-e, and are much freer 

 from sand, or grit, than most drift clays, and hence are to be recom- 

 mended for those purposes that require such a clay. These chiefly 

 lie in the upper part of the formation. 



It may be remarked, in view of the unwarranted expenditures that 

 are likely to be made under false advice, or superficial knowledge, that, 

 however much any portion of this formation may resemble, in general 

 aspect, any portion of the Coal Series, there never has been, and there 

 is no likelihood that there ever will be, any workable deposit of coal 

 found either in, or beneath it. iSTo reliance whatever is to be placed on 

 the physical nature of the rock. The fossils found in it, which, in this 

 and other formations, are given with unusual fullness, demonstrate 

 the litter folly of enterprises looking to the discovery of coal in or be- 

 neath this formation. 



Distribution and Local Details. The most southerly point at which the Cincinnati 

 beds have been observed in outcrop is near the middle of the south line of Sec. 9, in 

 the town of Eagle, Waukesha county. The exposure at this point is very slight, and 

 consists of impure limestone, a portion of it havuig an earthy and a portion, a gi-anular 

 crystalline texture, fuU of small cavities, and speckled with ocherous spots. A sufficient 

 number of imperfect fossils are present to determine the position of the rock, which is 

 near the upper face of the formation, but not immediately beneatli the Niagara hme- 

 stone, there being a bed of clay or clay-hke shale between. In this vicinity the drift 

 contains many blocks of a fine-grained, dark clay shale, and a lighter colored, olivaceous 

 gray, arenaceous rock, having a somewhat shaly structure. The two kinds are not un- 

 commonly united in one bowlder, but the former soon disintegrates on exposure. Tlie 

 slaty portion also contains many comminuted fragments of Ungula, provisionally iden- 

 tified as Lingula Mag^mketa, and of indistinct graptoUtic remains, similar to Clima- 

 cograptus. As this is a very soft rock, and the blocks ajce little worn, and are essen- 

 tially confined to this vicinity, where the glaxsial moraine crosses the Cincinnati belt, it 

 is safe to conclude that it forms one of the members of the Cincinnati gi-oup at this 

 point. This is confirmed by the fact that precisely similar rock occurs between 150 and 



