14 
CONCLUSIONS 
The sediments which formed the rocks of the Anticosti 
sequence are wholly of shallow water origin and they teach, in 
a manner which is not open to question, that the deposits of a 
shallow Palaeozoic sea varied widely both in the character of 
the sediments and in its faunas. Were deeper water concerned 
in the deposition of these sediments it is possible that the varia- 
tions of both kinds would not be so great. The sequence cer- 
tainly teaches that sediments and faunal variations are to be 
expected in the deposits of shallow seas and, in particular, in 
those of restricted shallow seas as so many of the seas of the 
Palaeozoic are considered to have been. The number of Palaeo- 
zoic cases of lateral gradation recorded are few and the writer 
believes they have not been found to the extent that they are 
present because the study of the deposits has not been ap- 
proached from the viewpoint of lateral gradation. Further 
investigation, probably, will show that many units now con- 
sidered distinct formations with vertical relationship to each 
other will be found to lie on the same stratigraphic horizon. If 
this be true, there will be no necessity to postulate distinct 
invasions of faunas, separate troughs of sedimentation with 
many land barriers and tilting of the areas on opposite sides of 
the barrier to submerge first one side and then the other. 
Fossil faunas should be studied with the knowledge that 
organisms are controlled by environment and that environments 
vary within wide limits. If index species be not present, it 
should be considered whether the environment admitted their 
presence before it is decided that some barrier prevented their 
entrance. 
