SKETCH OF CHARLES HENRY HITCHCOCK. 265 



first described as horsebacks in Maine, about seventy of them having 

 been described in the report of 1861 and 1862. It was not till after 

 the description of the Swedish Osar that the nature of these lines or 

 ridges was understood; and now they were found in every promi- 

 nent valley in New England, as attendant upon the recession of the 

 ice sheet. Professor Hitchcock gave the correct name of these ridges 

 in his Elementary Geology, 1860; while for many years subse- 

 quently they were erroneously called hames, even in the geology of 

 New Hampshire. 



Professor Hitchcock gave the name of Champlain to the fossilif- 

 erous clays associated with the till of the Atlantic coast. The term 

 has come into general use as connected with the melting of the ice in 

 the latter part of the period. Because of the presence of boreal 

 species, and of analogies with similar deposits in Europe, Professor 

 Hitchcock has asked the question whether there may not have been 

 a Champlain glacial epoch posterior to those named farther in the 

 interior of the country, the Kansan, Iowan, and Illinoisian epochs. 



Those who explore the geology of northern New England have 

 to deal with crystalline rocks of various ages, and the opinions of our 

 best geologists have not been in agreement respecting them. Pro- 

 fessor Hitchcock was the first to make a geological map of New 

 Hampshire, and he also demonstrated the anticlinal nature of the 

 Green Mountains of Vermont. His teachers had inculcated the view 

 that these eminences belonged to a synclinal disposition, coupling 

 this with theoretical assertions as to their age and metamorphism. 

 Finding their main principle to be erroneous, he naturally disparaged 

 their theories, though more recent studies are eliminating many of 

 the schists from the Archaean. All the later explorers in the field — 

 Canadians and members of the Geological Survey — accept a pre- 

 Cambrian anticlinal in the heart of the Green Mountains. 



The distribution of the New Hampshire formations was made out 

 for the most part before any assistance was derived from the labors 

 of Dr. G. W. Hawes and other petrographers. Twenty years ago, 

 at the date of the final publication of the New Hampshire maps, the 

 doctrine of an igneous origin of the crystalline schist had hardly been 

 hinted at. What seems elemental to the modern petrographer who 

 has acquired his technical education since 1890 was unknown then, 

 and the classification given in the report may not agree with that now 

 taught. In the midst of the diverse views entertained, Professor 

 Hitchcock classified the rocks of northern New England according 

 to this principle: rocks that are identical in petrographical composi- 

 tion are assumed to have had the same origin, and to be synchronous. 

 Professor Hitchcock was almost the first of American geologists to 

 employ the petrographer as a help to the understanding of the crys- 



