56 
very thin layer or film at the sediment surface which should be 
fairly fluid and mobile. ‘When samples are taken with a snapper, 
it is probable that this layer is disturbed both during the actual 
collection and also by the washing received during retrieving the 
snapper through the water colum. When samples are taken with a 
corer, this surface layer usually remains intact until the core 
is removed from the barrel at which time considerable distortion 
can occur. In either case, when the sample is taken for analysis, 
variable proportions of the surface and subsurface layers are 
included and results will not be comparable nor will they express 
the maximum surface populations. For the future program dealing 
with this problem, a new type of sampler has been devised that 
captures the entire surface layer of a given area of sediment. 
If the total sample is then used for preparing the required 
dilutions, one would determine the coliforms per wnit surface 
area which is the key parameter in this problem. 
Because of the sampling difficulties, it is believed that 
the counts obtained in the various sediments are minimum counts 
and that much higher populations may occur in a thin surface 
layer. Whatever the quantitative difficulties inherent in the 
data, there is no doubt that the organisms detected are true 
coliforms of sewage origin and not peculiar marine bacteria that 
happen to give positive confirmed tests. Whether the detected 
coliforms have survived in the sediments for long periods of 
time or whether, alternatively, they are of recent deposition 
cannot be decided. There are certainly enough coliforms in the 
solids settling from the Whites Point and Orange County outfalls 
to account for the observed sediment population in those localitiese 
