Mar., 1910.] Pennsylvanian Limestones. loi 



appear to be closer than they really are. Ordinarily it is not 

 possible in a limited outcrop to determine whether undulation 

 exists or not. Therefore in sections where limestones are shown 

 to be unusually close together or unusually far apart it is only 

 fair to suppose that undulation is probably the cause provided 

 the difference be not over 15 to 17 feet as no undulation observed 

 exceeds that measurement. 



In the above quarry the rise and fall was not observed to 

 exceed 6 or 7 feet and no definite order was discovered as the 

 rising and falling occurs, no matter in what direction the obser- 

 vation be made. The limestone merely conforms to the topog- 

 raphy of the sea bottom on which it was laid as a mud without 

 becoming thicker in the depressions and thinner on the elevations 

 of that bottom. Had the mud or ooze been considerably greater 

 in specific gravity than the water in which it was laid it would 

 doubtless have glided slowly into the depressions where the 

 greater slopes occur and thus cause the upper and lower surfaces 

 to be less parallel than we find them. 



As nearly as could be determined from a topographic map the 

 top of the Vanport lies at IISO above sea as seen in the hill-top 

 directly north of the quarry and the Putnam Hill lies 37 feet be- 

 low, or 1 143 above sea as measured in the northeast corner of the 

 quarry. 



The following section measured near the center of the quarry 

 represents the character of this limestone fairly accurately. 



Feet Inches 



Brown arenaceous shale 16 6 



8. Limestone layer 1 7 



7. Parting, calcareous shale U 2 



6. Limestone layer. . , 1 4 



5. Limestone layer 7 



4. Limestone layer 1 11 



y. Limestone layer 1 8 



2. Parting, thin shale 



1 . Limestone layer 11 



Coal ' 11 



No. 8, or the top layer of liinestone, is perhaps the most dis- 

 tinct layer in the quarry and is readily recognized in any part of 

 the quarry where it has not been cut away by the ice. The 

 shale parting beneath gives it the well marked separation from 

 the next layer. On weathering it tends to split up into numer- 

 ous thin layers and does not appear to be as pure a lime as the 

 lower layers. 



No. 7 is a conspicuous parting of bluish calcareous shale of 2 

 inches thickness. It is the most sharply defined and constant 

 plane of separation in the quarry. 



