PRESERVATION 25 
which peopled the world in former periods have been lost by this 
means. 
And lastly, it must ever be borne in mind that, as yet, our 
knowledge of the stratified rocks of the earth’s crust is very limited. 
In course of time, no doubt, this deficiency will be to a great 
extent made good; but it will take a long time. Already, within 
the last thirty years, the labours of zealous geologists in the 
colonies and in various countries have added largely to our know- 
ledge of the geological record. Still, only a small portion of the 
earth’s surface has at present been explored; and doubtless one 
may look forward to future discoveries of extinct forms of animal 
and plant life as wonderful and strange as those that have been 
of late years unearthed in the “far West,” in Africa, and India, 
The Siwalik Hills of Northern India offer a rich harvest of fossils 
to future explorers. Already one remarkable and large horned 
quadruped has come from this region; and it is known that other 
valuable treasures are sealed up within these hills, only awaiting 
the “open sesame” of some enterprising explorer to bring them 
to light. 
As previously pointed out, deposits formed in lakes are the 
most promising field for geologists in search of the remains of old 
terrestrial quadrupeds and reptiles; but, unfortunately, such 
deposits are rare. 
It is very much to be regretted that the carelessness and in- 
difference of ignorant workmen in quarries, clay-pits, and railway 
cuttings have sometimes been the cause of valuable fossils being 
broken up, and so lost for ever. Unless they are accustomed to 
the visits of fossil-collectors who will pay them liberally for their 
finds, the men will not take the trouble to preserve any bones 
they may come across in the course of their work. (Examples of 
this negligence will be found on pp. 41, 65, and 295.) But when 
