studied under a high-powered microscope rather than under the usual low- 

 powered stereoscopic type. 



At the present time little is known about these comparatively newly discov- 

 ered foraminifera. Since most of these forms have a large initial chamber, it is 

 believed that they may be closely related to the megalospheric generation in the 

 foraminiferal life cycle. The current belief is that these minute foraminifera repre- 

 sent another stage in the life cycle of foraminifera. Not only are the same genera 

 recognized in the microforaminifera as in the small foraminifera, but in some 

 instances, the same species are found in both groups. 



It is interesting to note that in the preparation technique employed for the 

 liberation of the microforaminifera, the sample is treated with 52 percent hydro- 

 fluoric acid, which, instead of destroying the calcareous tests of these microfos- 

 sils, changes them from calcium carbonate to calcium fluoride. It is obvious that 

 only those with calcareous tests are preserved, since the hydrofluoric acid would 

 destroy those with siliceous tests. 



Small Foraminifera (PI. 11-111, figs. 5-14) 



The small foraminifera have been used more extensively in oil company 

 laboratories and on well sites than the other two types. More is known about 

 them because early workers recognized their stratigraphic value in subsurface 

 studies. No major mechanical difficulty is encountered generally in freeing them 

 from the enclosing sediments. They are used widely for correlation as well as 

 for age determination. Some forms, because of their restriction to certain en- 

 vironments, serve as paleoecological indicators. The planktonic forms are es- 

 pecially useful for long-distant correlation. Because of the extensive literature on 

 small foraminifera, the writer has purposely restricted his discussion of these 

 very important microfossils. 



Large Foraminifera (PI. 11-111, figs. 15-22) 



The large foraminifera include such families as the Orbitoididae, 

 Discocyclinidae, Miogypsinidae, and the Fusulinidae. They are commonly found 

 in carbonate rocks, and thin sectioning is generally required for their identifica- 

 tion. In the field, a whetstone and a hand lens may be the only tools needed for 

 the general recognition of a particular genus. However, as this group of fora- 

 minifera has not been widely studied by oil company paleontologists in this coun- 

 try, the experience of a specialist is often required for positive identification. 

 The fusulines are the largest and most complex of the late Paleozoic foraminifera. 



Radiolaria (PI. 11 -IV, figs. 13-16) 



Radiolarians are marine Protozoa of long geologic range, supposedly pre- 

 Cambrian to Recent. Their perforated tests are distinguished from other micro- 



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