Report on the Geology and Topography of a Portion of the Lake Superior Land ... - John Wells Foster, Josiah Dwight Whitney - Google Libros

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CONTENTS.

CLASSIFICATION AND NOMENCLATURE OF THE ROCKS.

Tabular arrangement of the different formations, 2. Terms defined, 2. Relations of

the igneous and aqueous formations, 2. The Azoic system, 3. The Silurian sys-

tem, 3. Confusion in nomenclature, 4. Synonomy of the groups in different

regions, 5. Explanation of the general map and section, 5-7.......

THE AZOIC SYSTEM.

Various crystalline schists forming the primeval crust of the earth, 8. Contortions to

which they have been subjected, 8. Presence of igneous rocks, 8. Condition of

the earth at the time of their formation, 8-9. Effects of metamorphism, 9-10.

This system characterized by an entire absence of organic remains, 10. Supposed

causes of their absence, 10-11. Geographical distribution of these rocks on the

northern coast of Lake Superior, 11-14. Divided into two groups, 11. Associated

igneous rocks, 12-13. Metallic contents, 13. Their relation to the Silurian

strata, 14. Their distribution on the southern shore, 14-19. External cha-

racters, 14. Igneous products, 16-17. Lines of lamination in slates, 20. Prev-

alence of iron, 21-23. Difficulty of estimating the thickness of this group, 31.

Contortions of the strata, 31. Remarks on the existence of this system in other

parts of the world, 33-35..

GRANITE ROCKS OF THE AZOIC PERIOD.

Character of the scenery

Range and extent on the

Granite, 36. Its composition, 36. Mode of formation, 36.

where it prevails, 36. Peculiarities of structure, 36-37.

northern shore, 37-38. Its external characters, 37. Range and extent on the

southern shore, 38-48. Greenstone dykes, 38-39. Section between Lake' Supe-

rior and the mouth of the Escanaba river, 41-45. Section from Keweenaw bay to

the mouth of the Menomonee, 45-48. Character of the granite in the western

portion of the district, 47. Age of the granites in this region, 48. Mineralogical

composition, 48. Economic value, 48-49. Trappean rocks, 49. Intensity of

igneous action during this epoch, 49....

THE IRON ORES AND ASSOCIATED ROCKS.

Reference to the general map and section, as to the extent of the iron-bearing

rocks, 50-51. Map of the iron-region, 50. General distribution of the localities of

iron, 51-52. Description of particular deposits, 52-57. The iron cascade, 52.

Jackson company's location, 54. The Cleveland location, 55. The iron beds of

the Machi-gamig, 56. Near the Menomonee river, 57. Occurrence of the ores

of iron in other districts, 58-65. In Scandinavia, 58-59. On the island of

Elba, 59-60. In the Ural mountains, 60–61. In Missouri, 61–63. In northern

New York, 63-64. In Massachusetts and Canada East, 64-65. Theoretical

considerations, 65-68. Résumé, 69.

Chemical examination of the iron ores, 70-77. Method of analysis adopted, 70-71.

Occurrence of foreign impurities in most ores, and their effect on the quality of the

iron, 71. Methods adopted to detect these impurities, 71-72. Their absence in

the Lake Superior ores, 77. Analyses of ores from various localities in this

district, 73-77. Remarks on the results, 77. Metallurgy of the iron ores, 77-81.

The Catalan forge, 78-79. The method of working these ores, 79-80. The tenacity

of the iron, 80. Cost of production of a ton of iron, 81. Occurrence of other

ores, 81-82. Other economic materials, 82-84.....

COMPOSITION OF THE TRAPPEAN ROCKS.

The terms trap and trappean rock generic, 85. Varieties of rock which have been

included under that name, 86. Their mineralogical composition, 85. Importance

of these rocks in our district, 86. Trappean rocks associated with the Potsdam

sandstone, 86. Analysis, 86-91. Probable analogy with Dolerite and Anamesite,

90. Occurrence of them in beds, 91. Trappean rocks of the Azoic system, 91-94.

Analysis, 92-93. General remarks, 94.......

Alphabetical list of minerals occurring in the Lake Superior district, with analyses

and remarks....

LOWER SILURIAN SYSTEM.-POTSDAM AND CALCIFEROUS SANDSTONE.

General characters of the members of this system, 110-113. First traces of organic

life, 111. Ancient limits of the oceanic basin, 111. General remarks on the

identity of the groups, 111-113. Potsdam sandstone, 113-134. Organic remains,

129-133. Range and extent, 113. Lithological changes, 114. Attempts to

identify it with the New-red, 114. Its development on the northern shore of Lake

Superior, 115-117. Evidences of volcanic action during this epoch, 115-116. Its

development on Isle Royale, in connexion with volcanic products, 116. Fiords,

116. Monument rocks, 117. Its development on the southern shore, 117-131.

Keweenaw Point and the Ontonagon region, 117-118. Examples of diagonal

stratification, 118. Its character and relations to the preexisting rocks at Granite

Point, 119. Carp river, 123. Presqu'isle, 121. Fissures, 120. Grand island,

124. The Pictured Rocks, 124–129. Miner's Castle, 126. The Amphitheatre,

126. Sail Rock, 128. The Grand Portal, 128. The Chapel, 129. Examples of

diagonal stratification, 130. The Grand Sable, 131. The extension of the sand-

stone eastward to the north shore of Lake Huron, and westward to the Menomonee,

131-134. Occurrence of Trilobites, 133. Its development in Wisconsin, 133.

Sandstone of the Mississippi and St. Croix rivers identical with the Potsdam of

New York, 133. Repetition of the causes which produced it, during the deposi-

tion of the Calciferous, 134. Calciferous sandstone, 134-135. Range, extent, and

mineral characters, 135. The want of horizontality in the detrital deposits not

necessarily evidence of disturbance, 136. Review of the various opinions as to the

age of this sandstone, 137-139..

Chazy, Birds-eye, Black river, and Trenton limestones, 140-148. Their intimate

association in this district, 140. Their range and extent, 140-145. Organic

remains, 142–145. On the St. Mary's river, 140. On the Escanaba, 141-144.

On Rapid and Whitefish rivers, 144-145. At Little Bay des Noquets, 144.

Along Ford and Cedar rivers, and the shores of Green Bay, 145. In Wisconsin,

145-147. Along the Fox river, and the shores of Lake Winnebago, 145-146. At

Plattsville, 146. At Galena, 146-147. The Galena, or lead-bearing limestone, a

distinct member of the lower Silurian series, not recognised in New York, 147.

Not a portion of the Cliff limestone, 147. Hudson river group, 148-151. Its

development on Drummond's island, 148. At Pointe aux Baies, 149. Organic

remains, 149-150. Its identity with the Blue limestone and marls of Ohio and

Indiana, 149. Lithological characters, 150. This group the true termination of

the lower Silurian series, 151....

UPPER SILURIAN AND DEVONIAN SERIES.

Clinton group, 152-156. Its development on Drummond's island, 153. On Big Bay

des Noquets, 153-154. On the eastern shore of Green Bay, 153-154. Fucoidal

markings, 154. Tracks and trails of animals, 155. Its prolongation into Wisconsin,

155-156. At Hartford, 155. Conditions of the ocean at this period, 156.

Niagara group, 156-161. Range of some of the fossils, 157. Its development on

Drummond's island, 157. Fossil contents, 157-160. Character at Point Patterson

and Pointe Detour, 158. Summer islands, 158. Peninsula of Green Bay, 158-159.

Lithological characters, 159-160. Section at Big Bay des Noquets, 159. Ancient

coral reefs, 159. Probable condition of their growth, 159. Thickness of the

Niagara and Clinton groups, 160. Onondaga salt group, 161–163. Its external

characters, 161. Range in this district, 161-162. Organic remains, 162. Missing

groups which occur in New York, 162. Evidences of ancient denudation, 163.

Source of various economic materials, 163. Devonian system, 163-166. Upper

Helderberg series, 163-166. Mackinac limestone, 164-165. Gros Cap, 164.

Island of Mackinac, 164-166. Arched Rock, 164. Sugar Loaf, 165. Fossil

contents, 166............

MISCELLANEOUS OBSERVATIONS ON THE PALEOZOIC SERIES.

Extension of this series into Wisconsin, 167-176. Section by Mr. Lapham, 167-171.

Mr. Hall's remarks, 171-172. Section by Mr. Whittlesey, 173-176. On the

origin of the basins of Lake Michigan and Lake Huron, 176-177. Mr. Hall's

remarks, 177. Mr. Whittlesey's observations on the thickness, bearing, and incli-

nation of these groups, 177-183. Evidences of denudation and subsidence during

the deposition of these groups, 183-185. Effects of oscillations on animal life,

CHEMISTRY AND ECONOMIC GEOLOGY OF THE PALEOZOIC SERIES.

Prospects of the mining interest in the Copper Region, 190. Sandstones and conglom-

erates, 190. Their chemical and mineralogical composition, 190-191. Their eco-

nomical application, 191. Chemical examination of the limestones, 191-197.

Method of analysis, 191-192. Lower Silurian limestones, 192-194. Remarks on

the composition of the lower Silurian limestones, 194–195. Upper Silurian

limestones, 195-197. Marble of the Azoic series, 197. General remarks on the

analyses, 197. Theory of dolomitization, 197–199. Occurrence of soda, chlorine,

and sulphuric acid, 199. Probable origin of these substances, 199. Economic ap-

plication of the limestones, 199-200. For calcination, 200. Building materials,

200. Occurrence of metallic ores in the limestones, 201. Gypsum, 201-202....190-202

DESCRIPTION OF NEW AND RARE SPECIES OF FOSSILS FROM THE PALEOZOIC

Marine fossils from the Potsdam and Calciferous sandstones, 203-206. From the

Chazy, Birds-eye, and Black river limestones, and the Hudson-river group,

206-215. From the Clinton group, 215-220. From the Niagara group, 220-223.

From the Upper Helderberg series, 223-225. List of organic remains, 226-228.

General remarks, 229–231....

ON THE SUPERFICIAL DEPOSITS OF THIS DISTRICT.

Division into drift, terraces, and alluvial deposits, 232. Drift phenomena of the
northern coast of Lake Michigan, and western coast of Green Bay, 232-234. Of
the Menomonee, 234-238. Of the valley of the Manistee, 238-242. Of the

White Fish, 242. Of the Escanaba, 242–243. Glacial furrows and striæ, 243–245.

Rocks broken by drift agencies, 245. Origin of the limestone pebbles in the drift

of Lake Superior, 246–247..

Terraces of Mackinac, 248.

Their composition, 248-249. Their similarity with

those of the Baltic, 252. Terraces of the adjacent coasts and islands, 253. Their

relative age, 253. Lacustrine in their origin, 254. Denudation of the drift, 254.

The period of its denudation, 254-255.....

SUPERFICIAL DEPOSITS-CONTINUED.

Alluvial deposits, 256. Sand beaches, 256. Pebble beaches, 256. Alluvial marshes,

257. Subaqueous ridges, 258. Hooks and spits, 258. River-belts, 260. Bars,

260. Origin of hooks and belts, 261. Dunes, 263. Their origin, 266. Dune-like

ridges, 267. Ancient beaches and terraces, 268. Boulders at Saut Ste. Marie,

269. Ancient and present beaches of Lake Michigan, 271..

ON THE ELEVATION OF MOUNTAIN CHAINS.

Importance of the study of the structure of mountain chains, 274. Object of this

chapter, 274. Structure of mountains, 275. Contraction of the earth a fundamental

cause of the elevation of mountains, 276. Parallelism of the systems of elevation

of the same geological age, 276. Investigations of Elie de Beaumont, 277.

Systems of elevation in North America, 277. Systems of elevation in Europe,

279. Comparison of the direction of the European systems with those of

America, 281...

PARALLELISM OF THE PALEOZOIC DEPOSITS OF EUROPE AND AMERICA.

Field of investigation in this country a very extended one, 285. Circumstances

affecting the nature of the Fauna of the same deposits at various points, 286.

Parallelism of the paleozoic groups in England and the United States, 293.

Lower Silurian groups, 295. Potsdam and Calciferous sandstone, 295. Chazy,

Birds-eye, and Black-river limestones, 295. Trenton limestone, Utica slate, and

Hudson-river group, 295. Upper Silurian system, 299. Clinton and Niagara

groups, 299. Lower Helderberg series, 301. Upper Helderberg, 301. Devonian

system, 302. Species common to the Devonian and Carboniferous, 311.

Tabular comparisons, 318

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