A-14 



constructing new component species axes so that each succes- 

 sive axis accounts for the greatest fraction of the remaining 

 total sample variance. 



These new principal component axes were rotated to a 

 "best fit" position, defined by the Varimax criterion (Klovan 

 and Imbrie, 1971) . The principal components represent math- 

 ematically independent end-member samples (species or groups 

 of species) , with each real sample being described to a 

 lesser or greater degree by an appropriate mixture of these 

 end-members. Rotation of the components to a "best-fit" 

 position introduces no distortion or loss of information. 

 The value of this technique is that the composition of the 

 mathematically independent end-members tends to be close to 

 real, and therefore more readily interpretable, samples. 

 Each sample was then classified in terms of its faunal com- 

 position with respect to the identifiable end-member 

 assemblages. 



RESULTS AND DISCUSSION 



Substrates 



A variety of different substrates and habitats were 

 found within the study area. On the whole, canyons offer a 

 more heterogeneous environment in terms of substrate varia- 

 bility than does the slope. Silty sediment is the major 

 substrate found within this area, both in canyons and on 



