The Ohio Journal of Science 



Vol. XXII March, 1922 No. 5 



SOME SUB-SURFACE ROCK CHANNELS AND 



CAVITIES FILLED WITH GLACIAL 



MATERIAL. 



J. ERNEST CARMAN 

 Department of Geology, Ohio State University 



DESCRIPTION OF DEPOSITS. 



At Silica, in Lucas County, Ohio, about ten miles west of 

 Toledo, is a large quarry which shows a face about twenty feet 

 in height and about one-fourth of a mile long, extending N-S. 

 and facing east. The strata exposed are in the upper part of 

 the Lucas dolomite and they dip westward at an angle of about 

 five degrees. 



Along the south part of this quarry face at about 15 feet 

 beneath the top there was exposed in 1921 a zone of light 

 drab dolomite, three to four feet thick, containing a number of 

 cavities that are lined and partially filled with large crystals 

 of calcite of the dog-tooth form. These spaces, or former 

 spaces now partly filled, commonly appear as lense-shaped in 

 the quarry face and are one to three feet long and six to twelve 

 inches high. 



Associated with the dolomite and calcite of this zone there 

 is a considerable quantity of fine grained silt clay. Most 

 of it is greenish or greenish-blue in color, but brown and other 

 dark shades exist. Most of it is laminated, but some is compact 

 without laminae. It is very tough and when wet sticks to 

 the hammer and tears like putty. When dry it is very hard 

 and breaks with a direct even fracture. Most of this clay 

 is without grit. At many places the clay rests against and fits 

 around the projecting dog-tooth calcite cr^^stals. It was found 

 also in sharp lateral contact with the dolomite and even filling 



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