GRUNDY COUNTY, 193 



and deposition to river action, though principally consisting of the decomposed 

 shales and fire clays of the Coal Measures. 



During the autumn of 1868, the remains of a Mastodon were found at Tur- 

 ner's strippings, about three miles east of Morris, under eighteen inches of 

 black mucky soil, and about four feet of yellowish loam, and resting on about 

 a foot of hard blue clay which covered the coal. The bones were badly de- 

 cayed, and most of them were broken up and thrown away by the miners ; of 

 the remainder, Mr. Joseph Even, of Morris, with his usual zeal for science, ob- 

 tained and presented to the State Cabinet, a part of a thigh bone, a fragment 

 of a lower jaw, three teeth, and a few of the small bones. The locality is a 

 portion of the old river bottom, and, in the lack of personal observation, I am 

 uncertain whether to believe that the presence of the bones indicates that the 

 animal was mired and died here, or to suppose that the carcass was deposited 

 here by the river. 



The Coal Measure rocks of this county are too soft and too readily disinte- 

 grated to allow of the preservation of any scratches that may, at any time, have 

 been impressed upon their surface ; so that, although we find in the gravel 

 very numerous scratched and polished pebbles and boulders, it is within only a 

 very small area that striated and polished rock surfaces have been noticed. In 

 the southeast quarter of section 23, township 34 north, range 7 east, at Waters's 

 quarry of Trenton limestone, smoothly polished surfaces have been frequently 

 met with. In the southwest quarter of section 16, township 34 north, range 

 8 east, Collins's run exposes a small surface of the shaly limestone of the Cin- 

 cinnati group, upon which are plainly marked three sets of striao, running, by 

 compass, north 30 east, north 37 east, and north 50 east. In the southeast 

 quarter of section 19, of the same township, the surface of the black slaty shale 

 which overlies the coal at Pettys's shaft, is scratched and polished in a similar 

 manner. As these three localities, however, are all within the old river valley, 

 we cannot, with certainty, predicate upon these- facts the conclusion that those 

 scratchings and polishings are attributable to glacial action. In fact, these and 

 some other circumstances give some reason for assuming that they are results 

 of river action alone. At the coal mine, we find the outer portion of the shale, 

 next to the creek bank, broken up for several feet, and thoroughly mingled 

 with the drifted materials which here form an overlying bank of about fifteen 

 feet. This disturbance, as well as the grinding of the surface, we may fairly 

 attribute to the action of the creek while at its former level. But, while allow- 

 ing that, in these particular cases, river agencies are sufficient to account for all 

 observed phenomena, we must also record the frequent occurrence in the Drift 

 gravel of large and small boulders unquestionably planed and striated by glacia 1 

 action. These are especially abundant along the Mazon. 



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