AMERICAN GEOLOGY DECADE OF 1870-1879. 557 



remains for any length of time in contact with a porphyry the latter 

 will become decomposed, the alkalies being set free in the form of 

 carbonates. The carbonates, reacting on the iron-bearing solutions, 

 will precipitate the iron as oxides, which will fill the pores in the 

 porphyry made by the removal of the alkalies. The silica set free in 

 the process would be to some extent removed, but most of it would 

 remain. The silicate of alumina would be decomposed by bicarbonate 

 of iron in solution and removed in the form of a soluble hisilicate, as 

 explained by Bischoff. It is needless to say that these views were not 

 generally accepted. 



Next to Owen's Key to the Geology of the Globe, I know of no 



more extraordinary publication relating to American geology than 



that of the artist George Catlin, entitled The Lifted and Subsided 



Rocks of America, with their Influences on the ( )ceanic, 



Geology V /f70 °° Atmospheric, and Land Currents, which was published 



in London in 1870. 



One can forgive any amount of ignorance relating to tin 1 subject of 

 geology in a man of Catlin's profession, but it is not so easy to forgive 

 him for putting before an indiscriminating public opinions which are 

 founded on wholly insufficient, and in many eases visionary, data. 



Catlin had traveled extensivehy throughout the western portions of 

 North America and naturally had been attracted by the enormous 

 amount of erosion and uplift manifest in a treeless area. That his 

 thoughts should have been turned in this direction is not at all strange, 

 but his conclusions are such as can be accounted for onh T on the 

 grounds that he had received absolutely no training, had not learned 

 how to observe, nor how to reason from that which he saw. 



The most striking features of the work are those relating to the 

 cause of the Gulf Stream and the origin of the Gulf of Mexico. He 

 conceived that from both North and South America there issued two 

 large subterranean streams of water, one flowing from the north to 

 the south under the main axis of the Rocky Mountains, and the other 

 in an opposite direction along the main axis of the Andes. These 

 becoming heated through proximity to the volcanic fires in the region 

 of the equator, finally issued, giving the necessary volume and temper- 

 ature to account for the Gulf Stream. 



The origin of the gulf itself he imagined to be due to an undermining 

 of the crust of the earth and its subsequent falling in, through the 

 solvent action of the heated water, and he figures the continent both 

 before and after the catastrophe. a 



" Catlin's book was noticed in the American Journal of Science, L, 1870, and dis- 

 missed with the following curt remark: "The writer of this work, well known for his 

 travels among the American Indians, here treats of mountain drainage, upheavals, 

 metamorphism, making of mountain chains, sinking of mountains, and of the Indian 

 races of America. He presents his geological views and criticisms with great posi- 

 tiveness, which is consistent with the fact of his limited knowledge of the subject." 



