GE^OIyOGY OF IvA SAIvlvE COUNTY. 



59 



of a much harder stone. They are from three to five 

 inches wide, and project from two to six inches above the 

 g-eneral surface, and are in two sets, one following- a 

 northwest-southeast course, the other a northeast- 

 southwest direction, the lines being* made up of many 

 curves They descend four to five feet into the rock, 

 some being- very straig-ht, others curved and have the 

 appearance of being- made up of layers, the planes 

 being- perpendicular to the surface. A similar struct- 

 ure is seen in some g-reen shales on Covell creek, 

 and also in shale in Brewery Hill, two and a half miles 

 northwest of Ottawa, and in several other places. In 

 the shale they are evidently cracks in mud made 

 by drying- and afterward filled with sediment; but 

 sand beds do not crack from exposure to the sun, and 

 hence this does not explain the St. Peters case. A 

 curious limestone covering-, as far as exposed, covers a 

 small area on the upper road leading- to La Salle about 

 three miles north w^est of Ottawa, in the first ravine 

 crossed after ascending- the bluff, fifty rods west of 

 the crossing-. It appears to be made up of frag-ments 

 of older rock, somewhat water-worn but not rounded, 

 and forms a bed of hard rock eig-ht to eig-hteen inches 

 thick. 



A few rods up this ravine is a bed of blue shaly 

 clay, traversed by veins of red ocher clay. In these 

 clays are imbedded many hard limestone nodules from 

 four to sixteen inches in diameter. 



In the east part of Utica Township, on the land of 

 C. W. Esmond, on a low^ ridg-e about fifty-five rods 

 south of his residence, there is a bed of limestone 

 g-ravel of a remarkable character. The pebbles look 

 like short pieces, one-half inch to two inches long- and 

 one-fourth inch diameter of worm-g-nawed tw^ig-s. It 

 was free from sand or earth. We saw a similar g-ravel 



