ON THE ERUPTED ROCKS OF COLORADO. 



By F. M. Endlich, D. K S. 



CHAPTER I. 

 INTRODUCTION 



Since the earliest times the attention of observers has been directed 

 to those peculiar mountains which, iu the language of Pliny, "send 

 forth fire, smoke, and rocks." Active volcanoes first led to speculations 

 as to the interior of the earth, as to the conditions existing beneath the 

 solid exterior crust. Study, developing gradually from amid the mytho- 

 logical and fabulous legends of mediaeval times, began to compare the 

 various occurrences known to those who were considered the masters of 

 science and the magic arts. With the great era that dawned iu the 

 time of LiunsBus, the recognition and application commenced of such 

 features as seemed more or less correlated. Hypotheses were formed 

 upon various subjects, theories expounded, and life was infused into 

 what heretofore had merely been regarded as meaningless forms or the 

 accidents of a direct creation. 



In the course of time, after the famous and severe struggle between 

 Neptunists and Plutonists had commenced, the rocks composing mount- 

 ains and ranges were subjected to more critical- examination. The an- 

 alogous results were pointed out, as demonstrated by groups of varied 

 occurrence, and from these results were drawn conclusions based upon 

 the observations of existing phenomena. It was recognized that where 

 now nothing but rigid rocks were found, there had been at one time the 

 most violent demonstrations of force. Where rivers flowed and lakes 

 placidly reflected surrounding hills, fire and accompanying heat had 

 once reigned supreme. Then the path was indicated that in future 

 scientific research should follow, a definite direction was given to the 

 investigating mind, and reasoning from the known to the unknown was 

 slowly developed. 



In Europe, the cradle of our present sciences, the first important re- 

 sults were obtained, and to men like Buch, Werner, Beudant, Herschel, 

 and others are we indebted for the initiation of many ideas with regard 

 to the earth's former history that they obtained from the study of what 

 before their time had been but a sealed book of mystery. 



In every portion of the world, so far as hitherto explored, the evi- 

 dences of volcanic activity have been found. Our limited knowledge 

 permits, as yet, of no systematizing of their horizontal distribution. 

 Even of the existing volcanoes we can say but little, save that they oc- 

 cur in the vicinity of present shore lines. Inferring from this, we can 

 assume that the same conditions existed at the times when the enor- 

 mous masses of volcanic material were ejected in regions that now are 

 far inland. 



Erupted material is by no means confined to any one geological epoch. 

 The appearance of liquid or plastic masses upon the surface ot the earth 

 has occurred since the earliest times, since the formation of a rigid 



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