66 GEOLOGY OF ILLINOIS. 



baked appearance. Hanlly a trace of a fossil could be seen. An acci- 

 dent here, to our pocket level, prevented an accurate measurement of 

 this interesting mound. Crane's Grove, commencing about one mile 

 north of Bailey ville, and extending over several sections towards the 

 north-west, is another of those elevations, left standing when the sur- 

 rounding formation of the Cincinnati group was eroded and carried 

 away. The worked outcrop near Baileyville, furnishes stone fit for 

 ordinary foundation purposes, but entirely nnfossiliferous. East of the 

 Illinois Central Eailroad track, in the township of Silver Creek, some 

 isolated patches of the Cincinnati shales and clays may be noticed, but 

 the formation in this direction soon gives place to the Galena limestone. 



These quarries of the Cincinnati group afforded few fossils. In the 

 little streams and on the hills about Loran, the Ortliix tCKtmlhuiria and 

 Ortliis occidentalis may be found in some abundance ; but we have yet to 

 find a Cincinnati quarry, except along the .Mississippi river, abounding 

 in even characteristic fossils. 



The Trenton Limestones. This formation, as now recognized by geolo- 

 gists, embraces the Galena, the Trenton proper or Blue, and the Buff 

 limestones. These divisions are well marked and easily distinguish- 

 able, and in these reports we shall describe and refer to them by these 

 well known names. 



The Galena Limestone. Nearly three fourths of Stephenson county is 

 underlaid by this well known division of the Trenton rocks. And 

 inasmuch as the railroad cuts and the streams afford the best facilities 

 to study the geologic formations of these counties, we shall first pass 

 along them in our description of this wide extended member of the 

 group. The Illinois Central Eailroad enters the county at Warren, near 

 its north-western corner. It passes over a low, smooth prairie, without 

 outcrop or stone quarry to Lena. Waddam's Grove, which stands in 

 this prairie, shows that the Galena limestone underlies it. At Lena 

 there is a quarry and a lime kiln within a short distance of the town, 

 exposing some fifteen feet in thickness. In about two miles further 

 there is another. Both are on a little stream towards the north. Pass- 

 ing on towards the south-east the railroads exhibit several small sec- 

 tions in the top of the Galena beds, but does not afford any heavy sec- 

 tion, until Freeport is reached. Just west of the city, along the track 

 of the railroad, and near the banks of the Pecatonica river, in a low 

 range of hills, three extensive quarries are w r orked, furnishing stone for 

 lime, and for the large amount of building material needed. The first, 

 nearest the city, is worked about eighteen feet deep. The rock obtained 

 here is very soft, yellow, sandy, and full of cavities the size of a walnut. 

 Where heaps of it have been removed, a considerable amount of sand 

 is lef 'j scattered on the ground. The top layers of this quarry are so 



