KNOWLEDGE OF EARTH STRUCTURE 165 



heat into deeply buried and water-soaked masses of sedi- 

 ments ^ (see 30, 133, 1860). The germ of this idea of 

 aqueo-igneous fusion was far older, due to Babbage and 

 John Herschel, neither of them geologists, but such 

 sweeping extensions of it had never before been pub- 

 lished. Hunt had the advantage of a wide acquaintance- 

 ship with geological literature and chemistry. He wrote 

 plausibly on chemical and theoretical geology, but his 

 views were not controlled by careful field observations. 

 In fact he wrote confidently on regions which apparently 

 he had never seen and where a limited amount of field 

 work would have shown him to have been fundamentally 

 in error. A man of egotistical temperament, he sought 

 to establish priority for himself in many subjects and in 

 order to cover the field made many poorly founded asser- 

 tions. Building on to another Wernerian idea, he held 

 that many metamorphic minerals had a chronologic value 

 comparable to fossils staurolite for example indicating 

 a pre-Silurian age and on this basis divided the crystal- 

 line rocks into five series. Although there is much of 

 value buried in Hunt's work it is difficult to disentangle 

 it, with the result that his writings were a disservice to 

 the science of geology. Although carrying much weight 

 in his lifetime, they have passed with his death nearly 

 into oblivion. 



Marcou, with a limited knowledge of American geol- 

 ogy, and but little respect for the opinions of others, had 

 published a geologic map of the United States containing 

 gross errors. In support of his views he read in Novem- 

 ber, 1861, a paper on the Taconic and Lower Silurian 

 Rocks of Vermont and Canada. In the following year 

 he was severely reviewed by "T," who states positively 

 in controverting Marcou (33, 282, 283, 1862) that "the 

 granites (of the Green Mountains) are evidently strata 

 altered in place." 



"Mr. Marcou should further be informed that the granites 

 of the Alpine summits, instead of being, as was once supposed, 

 eruptive rocks, are now known to be altered strata of newer 

 Secondary and Tertiary age. A simple structure holds good in 

 the British Islands, where as Sir Roderick Murchison has shown 

 in his recent Geological map of Scotland, Ben Nevis and Ben 

 Lawers are found to be composed of higher strata, lying in 



