REPORT OF THE CHEMIST. 139 



Slicll-iiiail from JMarsliall Hall, Maryland, presented by Oliver N. 

 Bryant, is comj)osed of — 



Organic uiiittev imd moisture 2. O'.IO 



Carbouivte of liuie .'j4. 070 



Cra'bouate of luaglle^3ia .' 1. 30 1 



Phospbovic acid 0. ;5r>0 



Peroxide of iron and alimiiiia ~. 955 



Potassa and soda 1. 000 



Silica n8.291 



100. 000 



Greensand-marl, from the same locality, gives — 



Organic matter and moisture 1. 900 



Carbonic acid 1. 214 



Phosphoric acid 0. 653 



Peroxide of iron and alumina 2. 207 



Lime 9. 4G5 



Potassa and soda 0.800 



Silica 83.7G1 



100. 000 



A specimen of calcareous marl from San Jose, Santa Clara County, 

 California, presented by Charles G. Thomas, shows the following com- 

 j)Osition : 



Water, determined at 100- C 1.535 



Carbonate of lime 58. 360 



Peroxide of iron and alumina 7. 495 



Potassa and soda '. 0.250 



Silica 32.360 



Phosphoric acid a trace 



100. 000 



Two samples of marl from Prince George's County, Maryland, fur- 

 nished by F. W. Poor, give the following results: 



No. J.—Shcll-maiL 



Water, determined at 100^"' C 2.600 



Lime 32.910 



Carbonic acid 26. 429 



Peroxide of iion and alumina 4. 160 



Silica 33.901 



Phosphoric acid, potassa, and magnesia, each a trace 



100. 000 

 No. II.— Grcenmiid-marl. 



Water, determined at 100° C 4.025 



Lime 7. 260 



Carbonic acid .5.4.52 



Peroxide of iron and alumina 3.950 



Phosphoric acid 0.250 



Potassa and soda 0. 700 



Silica 78.303 



Magnesia a trace 



100. 000 



A specimen of gypsiferous marl from near Selma, Alabama, was for- 

 warded to the laboratory by E. Coon. On analysis, it showed the 

 following composition : 



Water, determined at 100° C 17.440 



Sulphate of lime 22. 355 



Silica and alumina 60. 205 



100. 000 



