The Goldschmidt-Lambe hypothesis of cardhouse clay mineral structure In undis- 

 turbed marine sediments recently appears confirmed. Hathaway (report in preparation) 

 demonstrated that high water contents correlate with large concentrations of skeletal 

 remains of diatoms, coccoliths, and other micro-organisms. It is hypothesized that 

 cardhouse structure will be modified by the presence of microskeletons; following 

 structural disturbance it is likely that rearrangement of cardhouse structure to a par- 

 allel orientation of platy minerals will be inhibited by microskeletons. Consequently, 

 it is suggested that sensitivity and thixotropic strength regain will tend to be inversely 

 related to the quantity of microskeletons. 



Complete thixotropic strength regain in deep-sea sediments following disturbance 

 caused by sampling is considered unlikely. 



It is suggested that variations in submarine core sensitivity may be related to 

 changes in pore-water salt content, however, data presently are not available for 

 evaluation of this idea. 



Modulus of elasticity, determined from compressive strength tests, ranged from 

 to 870g/cm 2 . 



A few clay-size (> 9$) samples from Areas A-C were examined for clay mineralogy, 

 In Areas A and B, mica was more common than mixed-layered montmorillonite-mica 

 (illite) or kaolinite; in Area C, mixed-layered montmorillonite-mica was more common 

 than either mica or kaolinite. 



Skempton (1953a, 1953b) showed that the plasticity index was a function of the 

 clay-size fraction, and he designated the ratio of the two parameters activity, which 

 was related to clay mineralogy. This relation has been confirmed by a number of 

 investigators, including Fisk and McClelland (1959) for late Quaternary Louisiana 

 continental shelf clays, and it appears valid for the few submarine sediments examined. 

 The spread of the reported data suggests a further extension of Skempton's classification, 

 which is considered tentative until more information from submarine sediments becomes 

 available . 



A general summary of the variation of the more important parameters with increas- 

 ing distance below the top of each core Is presented in Table 8. Although elsewhere 

 distances or depths are given in centimeters, in this table depths are in inches to 

 facilitate location of values in the plates and Appendix B. The extreme ranges of the 

 more significant measured or computed parameters found in this investigation are sum- 

 marized in Table 9 for ready reference. 



56 



