GEOLOGY OF THE WILD LANDS.

BY C. H. HITCHCOCK.

In the systematic account of the Geology of Maine in Part I, frequent allusions have been made to the character of the rocks in the more northern portion of the State, yet not as fully as was possible. As this section of the State is very little known, particularly the unsettled portions, we present the details of its geological structure, partly with a view to make the country better known, and incidentally to set forth its claims for settlement. The only system pursued will be a topographical one; i. e., a description of the geology of the different routes pursued by the different explorers. We shall first, however, present a general geological map of Northern Maine, and briefly describe it. Then we shall describe the geological features, so far as is possible without a repetition of what has gone before, of the following districts or sections; 1, a section from Charlotte to Presque Isle; 2, a section from Penobscot Bay to Ashland, 3, the region travelled by the exploring party last summer between Mattawamkeag and the St. John river; 4, the region between the mouth of Seboois river and Masardis; 5, the region of the St. John river; 6, the region of the Fish river lakes and the country from thence on the Aroostook river to Presque Isle; and finally the country south-west of Mount Katahdin.

The following are the different authorities upon which we base our statements, in the order in which they are given above: our own observations between Charlotte and Presque Isle, as well as between Ashland and Penobscot Bay, with the exception of a few miles of Mr. Houghton's explorations below Bangor; our own observations between Mattawamkeag and the St. John river; Dr. Jackson's observations between the mouth of the Seboois river and Masardis; our own observations upon the St. John river; Mr. Packard's report upon the Fish River lakes; and Mr. Houghton's

report on the Moosehead Lake and West Penobscot river region. Any facts derived from sources not indicated above will be promptly ascribed to them in the proper place.

Geological Map of Northern Maine.

This map has been hastily prepared from the observations of the different persons just mentioned. The rocks represented upon it are the following:

Granite and Syenite,

Talcose schist,

Mica schist and Quartz Rock,

Lower Helderberg group, (Upper Silurian,)

Oriskany sandstone, (Lower Devonian,)

Devonian rocks,

Calcareous slates,

Slates, probably Devonian in part, and Silurian in part,
Trappean and altered rocks.

The granite and syenite occur in several isolated patches, viz: near the Canada line on the Canada Road; on the south-east side of Moosehead lake; on the east shore of Brassua Lake; the great development in the Katahdin region; a small patch south-west of Masardis; others in Island Falls and Linneus; in Enfield; and extending from the region of Topsfield westerly and into New Brunswick, where it is largely developed on the east side of Schoodic Lake.

The talcose schist is found in two patches; the first a very extensive region on the upper St. John waters, whose limits are unknown; and the other extending from Patten northeasterly about 25 miles.

The mica schist associated with some conglomerates and a considerable quartz rock probably covers a large area, rather of a wedge shape, extending from northern Washington county, where it is narrowest, into New Brunswick, where it has not been traced by us beyond the St. John river. Two other strips of it appear in Washington county.

The Lower Helderberg group has been found only in patches, which are so represented, but are doubtless joined together, though in a way not understood. Its most Southern development on the map is at the base of Squaw Mountain on the south-west side of Moosehead Lake. We know not whether the rock is sandstone,

limestone, or mica schist. For its existence, we depend upon a list of fossils procured in that region by Mr. Hodge, one of Dr. Jackson's assistants. He also found the same fossils in limestone at Ripogenus Falls on the west branch of the Penobscot river. The Katahdin granite region may have severed the connection between this group of strata on the West and East Branches of the Penobscot, but we find traces of them on the East Branch as low down as Township No. 3. The first certainly known locality is on the Seboois river in rather small beds on Peaked Mountain in No. 6.. Another on the same waters is at the Second Seboois Lake in No. 7, R. 7. What we suppose to be the same belt of rocks, although it is not represented upon the map, is the bed of limestone and marble discovered by Mr. Basten in No. 7, R. 6. The same Helderberg limestone crops out upon Horse-shoe Pond in No. 5, R. 8. We lose sight of it now until we arrive at Ashland, for the reason that the country between has never been explored.. In Ashland it may be traced for nearly three miles, and extends without doubt much further in both directions. We have connected together upon the map the localities at Square Lake, and on Fish river south of Long Lake.

The Oriskany sandstone forms a wider belt, and its course can be followed more easily, because the rock contains characteristic fossils, and is so siliceous as to resist decomposition. Its most south-west locality is at Parlin Pond, then it is seen on Moosehead Lake, Chesuncook Lake, Telos and Webster lakes, and the Aroostook river. This region is easily mapped, except so far as doubt exists as to the width of the belt.

The rocks called Devonian are mostly sandstones containing fossils, which at the time of writing the report have not been determined. This group of rocks has been seen no further west than the East Branch of the Penobscot in Nos. 5 and 6. On the Seboois river they extend from Peaked Mountain in No. 4, to No. 7. Rocks of precisely the same character were not seen where this band is represented as crossing the Aroostook road, but on the line of strike red sandstones, etc., appear in Mapleton and in the moun-, tains south-west of Presque Isle. Also in an isolated patch on Mars Hill. A second set of sandstones appear in Ashland and eastward on the road to Castle Hill, as well as in the valley of the Aroostook river. The third belt of Devonian sandstones, etc., runs from Long Lake on Fish river to Long Lake or Madawaska lake in No. 18, R. 4.

The distribution of the calcareous slates, which are probably Upper Silurian or Devonian, is more simple, in Maine. They occupy most of the eastern part of Aroostook county in the first two ranges of townships, and a belt runs off from the principal deposit to the north-west corner of Patten.

Probably these calcareous slates are of the same age with the next heading on the map, of slates of uncertain Devonian or Silurian age. These are made to cover the regions between the Oriskany sandstone and the Devonian rocks, also between the two principal Devonian belts, and the region west of the Oriskany sandstone on the Canada road, and north-east of Chamberlin Lake. Lithologically, these slates resemble portions of the Oriskany sand

stone.

The clay slates cover an immense district. Part of them are Lower Silurian, as, for example, the immense deposits on the south part of the map. The immense district of clay slates on the St. John and Alleguash rivers may be Silurian or Devonian. Although these three classes of slates are indicated thus indistinctly, we have thought it better to represent them even thus poorly than not at all. Geologists will thus have some data upon which to speculate.

The last distinction upon the map is an exceedingly general one, including trap and porphyry rocks, trappean and associated con glomerates, and siliceous slates. The dikes, etc., are developed on Chesuncook Lake, East Branch of the Penobscot, and some portions. of Chamberlain, Eagle and Churchill lakes. The conglomerates occupy the rest of the borders of these lakes. are found on Moosehead Lake, the Travellers on the East Branch, sparingly upon the Seboois river and Eagle or Heron Lake, and very largely about Portage Lake, and the Long Lake of Fish river.

The siliceous slates