15(5 GEOLOGY OF ILLINOIS. 



Morrison belonging to the county, are of the same material. When 

 first quarried it is so soft that it can be hewn into any shape with an 

 old ax. It then appears unfit for building into any structure. But 

 when laid up in a wall it dries, seasons, and attains a firm texture. 

 The ease with which it can be worked recommends it, where dressed 

 stone is desirable. 



In some places the shales and rocks of the Cincinnati group are con- 

 sidered unfit for permanent mason work. It is supposed that atmos- 

 pheric agencies will eventually destroy their beauty and injure their 

 durability. But so far as tested, the quarries of the Cincinnati group 

 in this county furnish a lasting and desirable material for economic 

 uses. The layers are of convenient thickness, and break into any de- 

 sired size. The flag stones raised at Dr. PENNINGTON'S home quarry 

 are as large as need be wished for. This gentleman, with his accus- 

 tomed energy and a large expenditure of money, has two large quarries 

 in operation. He has also a stone yard in Sterling, where he can fur- 

 nish stone from his quarries in any quantity, and dressed into any 

 desired shape. He supplies this stone yard from the quarry near his 

 residence, and from the Hecker quarry in the township of Hopkins, 

 already referred to in this report. A handsomer looking lot of stone 

 than those quarried and corded up at the latter locality last fall, one 

 seldom ever sees. I hope merited success will crown Dr. PEKNINGTON'S 

 efforts to develop this branch of the material wealth and industry of 

 the county. 



As pertinent to this part of our subject, I here insert a table showing 

 the tests and properties of many samples of stone. Some of them are 

 from the quarries of the Cincinnati group just referred to. Others are 

 from the Niagara limestone from different localities in Northern Illinois. 

 The table is given entire, on account of the interesting nature of its 

 contents, and as furnishing a basis of comparison between our Northern 

 Illinois and some other rocks. It was furnished to myself and Dr. 

 PENNINGTON by the government officials on Bock Island. I regretted 

 that no specimens of the Galena limestone were present to be subjected 

 to the same trying ordeal. It will be seen from the table that the sam- 

 ples of stone from Dr. PENNINGTON'S Cincinnati quarries were in many 

 respects superior to the LeClare limestone, out of which the United 

 States Arsenal at Kock Island is built, and were almost equal to the 

 Joliet marble, out of which the United States Armory is being con- 

 structed : 



