142 JOUBNAL AND PROCEEDINGS 



extending over the whole surface and increasing in thickness in 

 spite of the opposition of powerful hypogene forces. Also, as the 

 cooling went on, the atmosphere became over saturated and rain 

 fell under tremendous pressure in scalding showers, while the 

 earth's surface was battered and buffeted by the powerful factors 

 acting upon it as the iron under the blacksmith's sledge. Finally, 

 a turbid, shallow sea surged 'round the earth from pole to pole ; 

 and here the earth entered upon a regular series of progressive 

 revolutions which gradually fitted it for the introduction of life. 



It is evident that, as the process of cooling goes on, the earth's 

 crust is proportionally thickening. Our superficial examination 

 would lead to the belief that the crust is not of very great thick- 

 ness. This assumption is supported by facts of which the follow- 

 ing are the most important : (i) Tlie temperature increases as we 

 descend ; (2) artesian wells furnish warm water ; (3) the evidence 

 afforded by hot springs and geysers ; (4) the elevation and depres- 

 sion of the earth's crust; (5) the phenomena of volcanoes and 

 earthquakes — all of which point to the presence of magma or 

 molten metal at no great depth (probably not more than 50 miles.) 



Men of science in their study of natural phenomena base their 

 researches upon the " Law of Uniformity of Nature " — that is to 

 say, they accept as true the supposition that similar causes produce 

 similar effects, and that a study of the laws governing our earth 

 will lead to a knowledge of those governing the universe. In such 

 wise, the geologist, by observation of prevailing phenomena, is 

 taught that the great stratified system of locks was and is being 

 formed by the deposition of sediment beneath water and under 

 great pressure. These sedimentary rocks are Nature's sepulchres, 

 where plants and animals from the most antiquated past have been 

 entombed and embalmed ; by means of them we can read pages 

 from the history of the globe. Again, from a consideration of the 

 discharges of volcanoes, the geologist sees that the material ejected 

 practically corresponds with huge masses of rock which have been 

 forced up through the stratified layers, and, therefore, applies to 

 them the term " igneous." (These rocks must have been formed 

 by internal convulsions.) 



