64 James Geikie — On Changes of Climate. 



todon and Elephant. Generally speaking, however, the "un- 

 modified drift" appears to rest directly upon the rocks, which are 

 polished and striated below it. But over wide regions in Labrador, 

 Canada, and the New England States, the lowest member of the 

 drift series is entirely absent : either because it never was deposited, 

 or else, having been laid down, it has subsequently been removed by 

 denudation. Dr. A. S. Packard says, "Nowhere did I see on the 

 coast of Labrador any deposits of the original Glacial clay or un- 

 modified drift. Upon the sea-shore it has been remodelled into a 

 stratified clay, and the boulders it once contained now form terraced 

 beaches."^ Professor Hind, however, mentions its occurrence capped 

 by sand and forming banks "rising seventy feet above the level of 

 the Moisie Eiver, twenty miles from its mouth." Thick masses of it 

 are encountered in Maine, where it presents precisely the same 

 character as in Scotland — a tough, unstratified clay, crammed with 

 angular and subangular, smoothed, and striated stones. In the State 

 of New York it is describe~d as " sometimes loose but frequently 

 partially aggregated by argillaceous matter that renders a pick 

 necessary to dig it."^ Mr. Whittlesey also makes frequent reference 

 to the occurrence in Michigan and Ohio of a deposit which he calls 

 "Hardpan," a firmly-compacted "mixture of clay, sand, and gravel, 

 or fragments of rocks in a confused or imperfectly stratified con- 

 dition." ^ This deposit I conjecture to be the same as our "Till." 

 In the regions described by Mr. Whittlesey it is always associated 

 with freshwater beds, and is included by him among the Glacial 

 drifts. 



The same geologist describes the occurrence of freshwater beds, 

 below glacial clay with boulders and sand and gravel. The fresh- 

 water beds contained remains of white cedar, pine, spruce, willow, 

 and other varieties not yet determined, and passed down into 

 laminated clays and " hardpan." He gives several sections to show 

 the character of these beds, of which the following is an example : 

 Artesian Well, Columbia, Ohio. 



Surface 215 feet above Lake Erie and 780 feet above tide. 



1. Soil 4 feet. 



2. Sand gravel and boulders 10 



3. Coarse sand 2 



4. Blue clay and boulders 4 



5. Fine quicksand 2 



6. Blue clay, inclosing a log 17 



7. Hardpan 3 



8. Quicksand 1 



9. Hardpan to cliif limestone 37 



80 „ 



Sometimes the vegetable remains in the freshwater beds are so 

 plentiful as to vitiate the water-supply. With the above section it 

 is interesting to compare the "journals" of borings made through 



^ On the Glacial Phenomena of Labrador and Maine. 



2 Geology of New York, part iv., p. 160 (Prof. "W. Mather). 



3 Smithsonian Contributions to Knowledge, vol. xv. 



