In general it may be answered that the surface of North America has been pretty well explored by government surveys and scientific expeditions and the geologic age of the larger areas determined.

Most important in determining the geologic sequence of the earth's strata are the fossil remains of animal and plant life.

A grouping of distinct species of fossils correlated with stratigraphic characters in the rocks determines these subdivisions.

When a collection of fossils is desired to represent a certain period, exploring parties are sent to these known areas.

Sometimes however, chance information leads up to most important discoveries, such as resulted from the work of the past two seasons in Alberta, Canada.
A visitor to the Museum, Mr.J.L.Wagner, while examining our mineral collections saw the large bones in the Reptile Hall and remarked to the Curator of Mineralogy that he had seen many similar bones near his ranch in the Red Deer Canyon of Alberta.