DESCRIPTION OF A LIMESTONE OF LOWER MIOCENE AGE. 285 
Papuan rocks, may in some strata as yet undiscovered, be 
found to occur in greater abundance than in the present 
limestone sample, and consequently yield a further supply 
of oily material, as they have been known to do elsewhere. 
3. Detailed Description of the Limestone. 
General Structure. 
The limestone of Bootless Inlet is a fairly compact rock, 
but shows a sub-brecciated structure in which the frag- 
mentary character was induced prior to the final cementa- 
tion of the constituents. 
A microscopical examination shows that in its initial 
stages of formation, this rock was a shallow-water shelly 
and coral sand, the particles being intermingled with frag- 
ments of a now partially or wholly decomposed volcanic 
rock of diabasic and andesitic nature, some fragments being 
quite glassy in structure as if derived from submarine 
ejections. The component organisms forming the rock are 
foraminiferal tests, among which are some gigantic species 
of Lepidocyclina, fragments of fish-teeth and bone, echinoid 
remains, polyzoa and calcareous alge. The separate 
organisms show signs of severe treatment, being not so 
much water-worn as angularly chipped and fractured, 
especially in the case of the larger foraminiferal tests. In 
most examples the peripheral edges of the large, peltate 
forms, as Heterostegina and Lepidocyclina, have been 
chipped and broken, and some of the organic material has 
been finely comminuted. Tidal and current action would 
scarcely account for this subangular, and even angular, 
condition of the shells, and many of the fragments are so 
sharply fractured as to lead one to conclude that fishes 
with crushing teeth, as the Labridce and Sparide, as well 
as other predatory animals, such as the echinoids and star- 
fishes, may be partly or wholly responsible for the peculiar 
condition of the material composing this limestone. 
