SS FOURTH FLOOR, SOUTH CENTRAL WING 
eruptions, while the nearby cases and pedestals contain relics of the ruined 
city of St. Pierre and the dust, stones and bread crust bombs that were 
thrown out in a white hot or molten condition by this volcano and by the 
Soufriére of St. Vincent. Some 30,000 people were killed by these out- 
breaks. Important geological facts were learned from the observation 
and subsequent study of the series of events. 
At the north end of the hall, there is the reproduction of part of a mar- 
velously beautiful cave that was discovered early in 1910 in the mining 
operations at the famous Copper Queen mine at Bisbee in the southeastern 
part of Arizona. The cave was formed by the dissolving action of water 
traversing joints in limestone, and its walls, roof and bottom were after- 
ward coated with calcite (cale spar) incrustations, stalactites and stalag- 
mites, some of which are dazzling white while others are colored green with 
copper salts or pink with iron compounds. 
In the alcove across the hall from the cave, the visitor may see the 
stump and part of the roots of a large tree from an anthracite coal mine 
under Scranton, Pa. Millions of years ago, in the geological 
period known as the Carboniferous, this tree grew upon the 
top of a thick swamp deposit of decaying vegetation which 
ultimately became a most valuable bed of coal. The stump was left in the 
roof of the mine when the coal was extracted for commercial and domestic 
uses. It fell to the floor years after the gallery had been abandoned and 
was discovered only through the chance visit of a miner. 
The cases along both sides and down the middle of the hall contain 
Fossilized 
Tree Stump 
geological and paleontological specimens. Paleontology is the science of 
the ancient life of the earth; its field is the study of the fossilized shells 
and other hard parts and the various kinds of imprints left by the animals 
formerly inhabiting the seas and lands, and preserved in deposits which now 
form our stratified rocks. As normally the upper layers of a series of strata 
are more recent than the lower, the fossils reveal the succession of life forms 
in the earth’s crust and thus are of the highest value and interest to the 
student of historical geology. Since, however, the remains of only a small 
proportion of the animals living at a given period are permanently preserved 
in the marine, river, lake and subaérial deposits of that period, the geological 
record of animal and plant forms is far from complete. Inasmuch as in- 
vertebrate animals are far less free in their movements than the vertebrate 
forms, they are accepted as the best determinants of the geological age of a 
bed of rock, even when remains of both kinds are found together. Inverte- 
brate life too appeared on the globe far earlier than vertebrate, and remains 
of certain species are abundant in the lowest (oldest) of our stratified rocks. 
The specimens in the cases are arranged to illustrate historical geology, 

