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REFACE. 
A COMPARISON of the Cretaceous Organic Remains of the political areas 
known as the States of Queensland and South Australia with those found 
within the l)oundaries of N. S. Wales, will demonstrate at a glance the 
superiority of the former as collecting grounds. This arises from the fact 
that the Cretaceous deposits of the areas in question, in a great measure, crop 
at the surface, whilst those of N. S. Wales, with the exception of the White 
Cliffs Opal Series, and possibly a few other isolated spots, are deep seated, 
and known only by borings and well-sinkings, lienee tlie apparent disparity 
in the number of species met witli in our State ; as, however, there is no 
reason to doubt the general continuity of the series from Queensland to South 
Australia through the north-western and mid-western portions of N. S. Wales, 
it is in every sense probable that this diminution in species is one solely due 
to the exi 2 ;encies of collecting. 
It was deemed advisable by Mr. E. F. Pittman to prepare a Monograph 
of the N. S. Wales Cretaceous Invertehrata as at present known, a task I 
undertook with much pleasure. 
R. ETHERIDGE, Junr. 
Sydney, April, 1902. 
