Section IV, 1887. [ 39 ] Trans. Eoy. Soc. Canada. 



IV. — Notes on the Physiography and Geology of AroostooJc County, Maine. 



By L. W. Bailey. 



(Read May 25, 1887.) 



In a paper read before this Society in May, 1886, and entitled " On the Silurian 

 System of Northern Maine, New Brunswick aud Quebec," the author, after making certain 

 comparisons between the rocks of these several districts, was led to express the opinion 

 that considerable areas in Aroostook County, Maine, which have been long regarded and 

 represented as of Devonian age, were more properly to be referred to the Silurian. Having 

 since had an opportunity of making a more extended examination of portions of the 

 county, as well as the regions in New Brunswick aud Quebec with which the former 

 was compared, he desires, in the present paper, to state a few additional facts which tend 

 to confirm the opinions then expressed, and at the same time to offer a few suggestions, 

 which may be of service to future explorers in the same field. 



The portions of Aroostook County which have been personally visited by the author 

 include the valley of St. John River, in so far as this forms a portion of the international 

 boundary — in other words to St. Francis Eiver, as well as beyond the latter to its tribu- 

 tary, the Allegash — and secondly, the country lying to the south and west of this valley, 

 so far as it is included between Fish liiver and Aroostook River. It is to the latter region, 

 lying almost wholly within the State of Maine, that more particular reference will here 

 be made. 



A glance at the topography and physical features of this region, as exhibited in any 

 good map, will be found to reveal some features of interest, which may help to explain 

 its geological structure. Of these, perhaps the most noticeable are the peciiliar position and 

 character of the first or eastern branch of Fish River. This latter is really little more than 

 a chain of lakes, embracing not less than five distinct basins. Long, Mud, Square and Eagle 

 Lakes, varying from two to twelve miles in length, and from one to two in breadth, which 

 are connected with each other, for the most part, only by short thoroughfares. They are 

 also very nearly upon a common level, and are bordered by land which, relatively to the 

 lakes, has usually bvit little elevation. In other words, they occupy the deeper portions of 

 a somewhat irregular trough, extending from the eastern limits of Long Lake, through 

 Mud and Square Lakes, to Eagle Lake, and even beyond the latter, iip the westffrn branch 

 of Fish River to Nadeau Lake, a total distance of twenty-five miles, with a probable change 

 of level to the forks of not more than three or four feet. To the north, this trough is 

 separated from the valley of the St. John by a range of somewhat prominent hills ; but at its 

 eastern end, in Long Lake, approaches the latter so nearly that not more than seven miles 

 of distance divides the two. Thus, by simply traversing this short interval, from French- 

 ville on the St. John to the head of Long Lake, one has before him a continuous water- 



