PROF. HARRIS. NOTES ON^ OUR LO(;AI. GEOLOGY NO. II. 165 



iar. It crops out on the banks of the river both above and below 

 the city Extending across the river from bluff to bluft", and as far 

 west as Cook's farm, this is found l)ut a comparatively short distance 

 below the surface of the ground. Whatever may be said of other 

 rocks we are about to notice, one thing is settled; this is continuous 

 and forms the solid basis on which the others all rest. 



In upward succession, resting on this non-fossiliferous rock just 

 described and represented by 6, we found a rock abounding in fossils. 

 Within the past two years it has been exposed at Le Claire's quarry, 

 being three or four feet thick; at the quarrj^ between Rock Island and 

 Moline, assuming a greater thickness; while in Cook's quarry it is 

 represented })y certain layers found at neither, and attaining twenty 

 feet in thickness. It is from this rock that the Corniferous fossils de- 

 scribed in the last volume of the publications of the Academy were 

 gathered. As at that time, so now: no traces of any of these fossils 

 are found in the ascending beds. 



This rock differs from those above and below it, not only in its fos- 

 siliferous contents, but is a pure carbonate of lime, and has been ex- 

 tensively burned for quick-lime both in the quarries between Rock 

 Island and Moline and at Cook's quarry below this city. By some 

 immense power of which we may speak hereafter, it has been brok- 

 en up and removed over the area where it had been originally de- 

 posited; and with the exception of its forming the bed of Rock Riv- 

 er as far as Milan, it is only found in place in the three quarries de- 

 signated. 



In their natural ascending ordei- we next have the brown Argilla- 

 ceous shales and gray and l)rown lime-stones of the Hamilton Group, 

 (these are denoted on the diagram by the letter c; at present they 

 are only found in place at the quarry between Rock Island and Mo- 

 line) exhibiting, in the face of the clif}', a thickness of between twen- 

 ty and thirty feet. They are not found either at LeClaire's or Cook's 

 quarries, nor are their equivalents found in our vicinity, the rocks 

 at Buffalo being simply their upward extension. As in the case of 

 the preceding rock h, so it is in this; at one time there is not the 

 slightest doubt that they occupied the whole distance over the area 

 we are considering, and everywhere resting immediately on the 

 harfl calcareous rock, represented by b. 



Next above this formation, in natural ascending order should come 

 what are called the Coal Measures- c?. These no doubt were co-ex- 

 tensive with and resting immediately on the Hamilton. Of these no 



