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The student of foraminifera is concerned, among other things, with the 

 relative numbers of living and dead benthonic foraminifera on the bottom surface, 

 and he needs undisturbed samples of the topmost few millimeters. The ecolo- 

 gist wants a census of the numbers of living creatures per unit area; because 

 most biological activity takes place in the upper layers of the sediments, he 

 needs a large, undisturbed sample, covering a known area, of these upper lay- 

 ers. The chemist needs samples, uncontaminated by stirring of the bottom 

 mud, of the water immediately above the bottom, in addition to comparatively un- 

 disturbed samples of the sediments from the surface down to as great a depth as 

 possible. The bacteriologist needs a core of sufficient dimension so that he may 

 dissect out an uncontaminated sample, and he requires that the sediments near 

 the surface be undisturbed because this is the zone of most intense microbial 

 activity. 



In order to study rates of sedimentation it is necessary that the sedi- 

 ments at different depths below the bottom surface be equally represented in the 

 sample. The use of carbon-14 and other similar methods for age determination 

 requires a large-diameter core which can be dissected into thin layers, yet pro- 

 vide enough material for analysis. 



In studying laminations and bedding structures, we need to know the later- 

 al variability. One of the ways in which this can be accomplished is by taking 

 multiple closely spaced cores, for example by the use of two or three gravity 

 corers rigidly attached in parallel as a "bident" or "trident". 



Few effective coring devices are equally effective in mud, sand and rock. 

 A corer which takes a long undisturbed sample of silt or clay will often not re- 

 tain sand, and will usually be brought up without a sample, but badly damaged, 

 on striking rock. No devices presently available to oceanographers can be de- 

 pended upon to recover a long undisturbed core of sand or an oriented sample of 

 rock outcropping on the sea floor. The problem of rock sampling beneath an 

 overburden of unconsolidated sediments has been partly solved by oil companies 

 exploring the continental shelf. A hole is jetted through the overburden with 

 hose and pumps, and a short core of the underlying rock, with orientation re- 

 corded , is obtained. 



In many cases it is desirable to obtain a large sample of one or more of 

 the constituents of the sediment. This is the purpose of such devices as the bot- 

 tom trawl and the Isaacs-Kidd "diving dredge", which separate out and collect 

 the larger organisms living on the sea floor, and such large-sized inorganic 

 components as rock pebbles and naanganese nodules. 



Core samples brought back to the laboratory can be studied in many ways. 

 Several books have been written on this subject and new techniques are constant- 

 ly being developed. Time and space do not permit even a brief review but it 

 may be sufficient to refer to the superb results obtained by Arrhenius, Petters- 

 son and their co-workers through the coordinated use of different techniques - 

 biological and mineralogical examination, chemical, x-ray, spectroscopic and 

 mechanical analysis, and determination of physical properties - on the more 

 than 5,000 feet of cores collected on the Swedish ALBATROSS expedition. Their 

 work shows that long cores of deep sea sediments can constitute an archive of 

 events in the ocean during the last million or more years, and as such merit the 

 same careful handling as a good librarian gives to the books under his charge. 



• The taking of long cores in the open deep sea is expensive, costing rough- 

 ly $100 per lineal foot. But this expenditure is partly wasted if the cores are 

 not properly treated after collection so as to preserve, in so far as possible, the 



