SCIENTIFIC SURVEY. 377 



D. SURFACE GEOLOGY. 



In our Preliminary Report we went largely into details upon the 

 geology of the Alluvial Period, or Surface Geology. Our defini- 

 tions of the various forms of the superficial deposits, as well as the 

 theories of their accumulation were there given so fully, that it is 

 now incumbent upon us merely to state whatever new fticts have 

 been brought to our notice during the past year, what new illus- 

 trations discovered, and whether any light has been thrown upon 

 perplexing points. Already we have incidentally alluded to cer- 

 tain phases of alluvial or drift action in our descriptions of the 

 country or of the older formations. Such remarks will not be re- 

 peated, nor will all the details of our observations be presented — 

 only the most striking points. 



A few very large boulders were noticed. One of granite is in 

 the water near the south shore of Sysladobsis lake. A boulder of 

 gneiss near Weld weighs by calculation more than 1,000 tons. 

 Another split in two is in Phillips. One of conglomerate twenty- 

 four feet long lies in the river St. John in number eleven. Near 

 South Paris there is a large pear-shaped boulder standing by the 

 side of a tree, and we should say it must be at least thirty feet high, 

 as it is more than half as tall as the tree. There should be a sketch 

 taken of this wanderer with the tree by its side. 



It was remarked as a fundamental principle in the science of 

 Surface Geology, that boulders are transported from ledges in 

 right lines, in the direction in which the drift agency operated. 

 Hence it is found that the course of the striae corresponds with 

 that taken by the fragments. Conversely it is true that if we find 

 boulders of some particular rock scattered over the surface, we 

 can always discover the ledges from which they were derived, 

 especially if the course of the striae in the vicinity is known. Now 

 there are several important varieties of boulders in Maine whose 

 source is unknown to us. Therefore we will mention them, in 

 the hope that some one will be able to trace them to their sources. 

 First there are the boulders of white statuary marble on the east 

 branch of the Penobscot river, (Matagamon,) between Medway 

 and the Grand Falls. Second, there are the valuable boulders of 

 magnetic iron ore in Phillips and Salem. Thirdly are the not less 

 important fossiliferous boulders in Phillips. Fourthly are numer- 

 ous boulders of red and grey conglomerates near the eastern border 

 of the State. They may have been derived from a formation con- 



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