104 PROCEEDINGS OF THE PHILADELPHIA MEETING 



the denser solution. When the concentration had reached a proper point, there 

 might then be precipitated on the bottom of the bay a single salt, such as 

 gypsum. This process might go on until all the gypsum of the lake was con- 

 centrated on the bottom of the bay. 



Further remarks were made by Dr. H. M. Ami and the author. 



CRYSTALLINE MARBLES OF ALABAMA ^ 

 BY WM. F. PEOUTY 



{Abstract) 



The crystalline marbles of Alabama occur in a long, narrow, and rather 

 well defined valley, which extends through Talladega and into Coosa County, 

 H distance of about 35 miles. The width of the marble-bearing portion of the 

 valley varies from one-fourth to one and one-half miles. The dip of the 

 marble in this belt is hi an easterly direction and at about thirty degrees. To 

 the southeast of the marble occurs the Ocoee phyllite mass, from which the 

 marble is separated for most of the distance by a thrust fault of variable throw. 

 The strike of the marble is consequently often different from the trend of 

 the valley, and the age of the marble at different places varies from Cambrian 

 to Ordovician. 



The present development is mainly in the central and southwestern portions, 

 where there is a greater thickness of the marble. 



The marble is highly crystalline, medium to fine grained, with markedly 

 ijiterlocking crystals and unusual translucency. Beds of talcose schist con- 

 stitute the main impurity. A number of grades of marble are marketed, rang- 

 ing from statuary-white through cream-white and blue-toned to the varieties 

 showing considerable clouding or banding by the greenish-toned schist. The 

 marble is largely used for interior dec-oration and commands a high price. 



The crustal movements in the field are well shown, locally, in the "slicks," 

 drag-folds, and elongated crystals, and the field offers interesting opportunity 

 for the study of the relation of movements to unsoundness. The development 

 work shows the benefit of careful prospecting for lines of unsoundness and 

 directing operations to conform to the lines of structural weakness. 



Presented l)y title in the absence of the author. 

 The section adjourned at 3.58 o'clock p. m. 



ANNUAL DINNER 



The annual dinner of the Society was held at the Hotel Walton, about 

 140 persons participating. E. 0. Hovey acted as toastmaster, and the 

 speakers of the evening were W. Liudgren, H. F. Osborn, C. D. "Walcott, 

 C. E. A^an Hise, W. W. Atwood, and F. R. Van Horn. 



I By permission of the State Geologist of .\labama. 



