944 T. W. VAUGHAN CHEMICAL DEPOSITS OF THE SEA 



found in the warmer parts of the ocean, or at least where the surface 

 temperature is high. 



Conclusion 



The investigations outlined comprise ascertaining the physical and 

 cliemical characters of a deposit, analyzing it to discover the source of 

 each constituent, evaluating each constituent, and classifying the deposit 

 according to the source of its constituents. The physico-chemical condi- 

 tions tliat determine the presence of the responsible depositing agencies 

 in eacli ])articular spot must be ascertained and deposits formed under 

 different physico-chemical conditions must be compared. By following 

 sucli a procedure we may hope to understand what is now happening in 

 the sea, and the knowledge thus gained may enable us to make dependable 

 deductions regarding the history of the sediments that engage our atten- 

 tion in our geologic researches. 



Explanation of Plates 

 Plate 41.— Artificial Sphei-ulites and Oolites 



Figure 1. — Splierulites bacterially formed in water from Great Salt Lake. 



X 100. (Preparation by K. F. Kellerman.) 

 Figure 2. — Spherulites bacterially formed from calcium acetate in water from 



Great Salt Lake. X 50. (Preparation by K. F. Kellerman.) 

 Figure 3. — Zonal spherulite inorganically formed in sea-water from Florida. 



X 350. 

 Figure 4. — Zonal spherulites inorganically formed in sea-water from Florida. 



X 700. 



Plate 47. — 'Natural Precipitates 



Figure 5.— Great Salt Lake oolite. X 100. 



Figure 6. — Aragonite needles out of mud from the west side of Andros Island. 



X 840. 

 Figure 7. — Small oolites ont of mud from the west side of Andros Island. 



X30. 



Plate 48 



Figure 1. — Bahaman elevated oolite. X 100, without traces of filamentous 

 algse. 



Figure 2. — Illustrates filamentous algse left after decalcification of a corallite 

 of Orhicella cavernosa (Linn.). X 100. 



Figure 3. — Thin section of OrUeella annularis (Ellis and Solander), with 

 filamentous algre in place. X 100. The presence of filamentous 

 algjp in oolite grains is adventitious. These organisms bore into 

 any calcium-carbonate structures that lie on the sea-bottom. 



