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 NOTES 
 
 J 
 
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 ON 
 
 THE GEOGRAPHY AND GEOLOGY 
 
 OF 
 
 LAKE HURON.; 
 
 By JOHN J. BIGSBY, M.D. F.L.S. M.G S. 
 
 MEMBEI, or THE MEDICO-CMlBUnCCAL SOCKTV OF LONDON, 40N0HAEV MEMBER OV THE AMEUUAN 
 
 GEOLOGICAL SOCIETY. 
 
 From the Transactions of the Geological Society of London. 
 
 LONDON: 
 
 PRINTED BY lUCHAHU TAYLOR, SHOE-LANE. 
 
 1824. 
 

 \ 
 
 XIV. — Notes on the Geography/ and Geology of Lake Huron. 
 Bv JOHN J. BIGSBY, m.d., f.ls., m.g.s., 
 
 MEMBER OF THE MEDICO-CHIRURGICAL SOCIETY OF LONDON, HONORARY MEMBER 
 OF THE AMERICAN GEOLOGICAL SOCIETY. 
 
 [Road Feb. 21, March 7 and 21, 1823.] 
 Sect. I. GEOGRAPHICAL SKETCH OF LAKK HURON. 
 
 Lake HURON U the third fVom the Atlantic Ocean of the great chain of 
 lakes, wliich occupy the {owv plateaux of the upper part of the valley of the 
 St. Lawrence. It receives the waters of Lake Superior by the Straits of 
 St. Mary, the small lake George, and, finally, by a series of basins and cur- 
 rents ; the whole connecting; channel being about 39 miles long. It discharges 
 into Lake Erie* by the river St. Clair, Lake St. Clair, and the Detroit River, 
 26, 25, and 24 miles long, respectively. 
 
 Lakes Huron and Michigan are parts of the same body of water, being se- 
 parated only by the strait of Michilimackinac. Their magnitude entitles 
 them to the denomination of independent lakes f . 
 
 The country to the north and north-east of Lake Huron is sterile, rocky, 
 and uneven, full of morasses, creeks, and ponds. It is always hilly, but sel- 
 dom rises more than 500 feet above the level of the lake ; and then in ridges, 
 rarely in cliffs. The higher grounds are naked rocks, with pine and birch 
 springing up in their fissures ; while the borders of the marshes and streams 
 (often of a clayey soil mixed with decayed vegetables) produce a profusion of 
 willows, poplars, shrubs, and long grass. 
 
 In these desolate regions, scanty tribes of Indians exist by the chase, disposing 
 of their furs to the wandering traders who visit them from Lower Canada. 
 
 The tract bordering the southern shore of this lake, and that also which 
 lies between Lake Michigan and the waters of St. Clair and Detroit, is highly 
 fertile. It is low and undulating, with frequent swamps and small lakes, 
 
 * Lake Michigan has no outlet but by the St. Clair : when, however, the waters exceed thoir 
 usual level by a few feet, a communication takes place with the Mississipi by the Illinois river. 
 
 t Mr. Hutchins, late geographer to the United States, calculated Lake Huron to cover 
 5,009,920 acres, and assigned to Michigan more than double that surface. 
 VOL. VI. 2 A 
 
i; 
 
 1' 
 
 176 Dr. BiGSBY on the Geography and Geology of Lake Huron. 
 
 and showing- occasional traces of limestone and sandstone. The mountains 
 delineated on some of the maps of this district are purely imaginary. Among 
 its forest trees are the oak (white and black), ash, walnut, elm, poplar, maple, 
 and various pines. The magnificent nation of Ottawas at J/Arbre Croche, 
 and the Indians on the river Saguina, liavc h)ng raised excellent vegetables. 
 
 Tlie country on the south-cast or Canadian shore, from tlie St. Clair to 
 Cabot's Head, is, on the south, low and damp, with extensive pineries ; but 
 nortlicrly it becomes stony and rugged, and its rivers are rapid. It is little 
 
 known. 
 
 The height of Lake Huron above tlie sea has not been ascertained with 
 accuracy, but may, without great error, be stated at 590 feet. The Commis- 
 sioners for constructing the western canal in the State of New York, esti- 
 mated Lake Erie to be 560 feet above tide-water in the River Hudson.— 
 Mr. Schoolcraft, who accompanied Governor Cass in 1820 to the supposed 
 copper mines in Lake Superior, gives 29 feet as the difference in elevation 
 between Lakes Huron and Erie,— which must be ne Me truth *. 
 
 The shape of Lake Huron is so extremely irregular as oidy to be learnt 
 from the accompanying map. Tracing its main shores loosely with a compass, 
 and omitting the lesser curvatures, its circumference is found to amount to 
 nearly a thousand miles. 
 
 The distinguishing feature of this lake is its intersection by the Manitou- 
 line chain of islands, which stretches E.S.E. from the promontory of the True 
 Detour, and in longitude 82° approaches within two miles of the northern 
 main land, the strait being nearly filled by an islet. The chain then suddenly 
 trends south-east to Cabot's Head. 
 
 Of the three portions into which the lake is divided by the Manitouline 
 chain, the two northern are full of shoals and islands, and that to the north- 
 west is comparatively narrow. The southern division is by much the largest, 
 and is deep, broad, and of free navigation. 
 
 Besides the Manitouline chain, and these three principal divisions of the 
 lake, the other points in the geography of Lake Huron demanding particular 
 notice are, the island of St. Joseph lately assigned to Great Britain, Michili- 
 mackinac and its vicinity and the Gulf of Saguina. 
 
 I have twice visited (in the years 1819 and 1820) the islands of St. Joseph 
 and Michilimackinac ; and on my second visit passed three months in then- 
 vicinity. In 1819 I descended the French river from Lake Nipissingto Lake 
 
 * One.third of the distance is horizontal; straight and tolerably unobstructed rivers occupy 
 the remainder. 
 
 Ji 
 
Dr. HiGSBY on the Gcograp/n/ and Gcologij of Lake Huron. 177 
 
 Huron, and coasted In a canoe tlie north main of the latter hike to the I^a»« of 
 St. Mary. I have been several times on the south coast, and olf the Gulf of Su- 
 .ruina. The rest of the lake I know only from the communications of my friends. 
 * The accompanying Map is a reduced copy, with additions, of one of four 
 times the size, compiled by David Thompsim Esq. British Astronomer under 
 the 6th and 7th Articles of the Treaty ofGlient, from surveys made by him- 
 self, and by Captain Owen, R.N., and from a map of the lake by Mr. Smith, 
 late Surveyor General of Canada. Mr. Thompson, assisted by the American 
 Astronomer Mr. Bird, and party, himself survey nl the north-western arm of 
 the lake and the Manitouline Isles as far east as the river Missasaga and the 
 Avestern end of the Grand Manitou. He also determined the position of the 
 False and True Presquisles, Point aux Barques, the commencement of the 
 River St. Clair, Cape Hurd, the fourth Manitou, Point Colles, and the Hill 
 Islands. Captain Owen's survey comprehends Cabot's Head and its vicinity. 
 
 I have added the Georgian Bay and the Straits of Michilimackinac from 
 Purdy's map of Cabotia, and part of Lake George from my own knowledge. 
 I have omitted many islands on the north shore, between the French and 
 Missasaga rivers, from their positions not being yet determined. Mr. Smitli's 
 map is only to be trusted in a very general way ; the printed maps of the Lake 
 are very erroneous. 
 
 I shall now describe those parts of Lake Huron which have been just enu- 
 merated. 
 
 The appellation of " Manitouline" or " Sacred" Isles is first observed in 
 Lake Huron ; and thence westwards is met with in Superior, Michigan, and 
 the vast and numerous lakes of the interior. 
 
 The islands of that name in Lake Huron are four in number, Drummond, 
 the Little, the Grand, and the Fourth Manitou, exclusive of the Isle of Coves, 
 and the other fragments of the great ridge that appears to have been once 
 continuous to Cabot's Head. They form a curving line 125 miles long ; the 
 direct distance between the extremes being only 97 miles. 
 
 Drummond Island is 24 miles long, and (on the average) 8 miles broad : the 
 greatest breadth being 12, and the least 2^ miles. It ranges nearly east ; and 
 at the western end approaches the main of the United States, there forming, 
 with the opposite headknd, the strait of the True Detour, the principal com- 
 mercial route to I^ake Superior. The strait is scarcely a mile wide, and, being 
 bounded by two promontories, is of very small extent. The coast of the 
 United States is here flat and woody, with morasses ; that of the island is un- 
 even, and loaded with large fragments of rock. The general surface of 
 Drummond is irregular ; the higher and middle parts rising to the height of 
 
 2a2 
 
178 Dr. BiosBY on the Geography and (uology of Lain Huron. 
 from 200 to 250 feet, and Inclininj,^ on either side to the water ; but often pre- 
 Hontinrlow >vlute precipices in broken lines on tbe sn.nnut or H.des ot the 
 slopes The low o-ronnds are swamps, <,ften extcnnve, and filled wUh n.osses, 
 aduutic plants and dcciiyinf-- timber. ,. . , . -a i i 
 
 The sonth coast of the island is bn.ke.. info small bnt deep bays, with shoal 
 points; and those on the west contai-ng- many islets, one ot vJuch has an 
 immensedepositof iron pyrites. , , .u^ 
 
 The north coast is distinguished by the magnitude ot Us bays, and by the 
 un>«ns of islands which crowd the contiguous waters. On one ot these 
 near Drummond, and 8 miles fr.>m Collier's Harbour, is the lud.an town ot 
 Portogannosee, consisting of log-huts a.ul gardens of Indian corn and po a- 
 t„es The northern coast is terminated on the East, in the strait called the 
 False Detour by a calcareous precipice of considerable beauty oOO yards long, 
 and 200-250 feet high. At the top it is a terrace of rock ; below it is sepa- 
 rated fron. the lake by a narrow shingle beach. This island produce, very 
 fine maple of the bird's-eye and curled kinds, pines, hemlock, cedar poplar 
 and birch. Few trees attain great size, as well from the scantiness ot the soil 
 as from the frequent conflagrations*. 
 
 The point which forms the west end of Drummond is the northern am ot 
 the bay containing Collier's Harbour, the most distant of the British md.ary 
 nosts This harbour is circumscribed to the diameter of half a mile by islets, 
 surrounding the front of the bay, through which i.lets there are three en- 
 trances It is oval, and possesses good anchorage ; but the wind, which brings 
 a vessel to anchor, either altogether prevents her departure, or renders it very 
 difficult ; and there are also many reefs in the vicinity. 
 
 On an acclivity in front of the harbour stands a village ot about oO wooden 
 houses and huts, with the barracks of the military built of logs on the right^ 
 The land around the village is cleared. It is hilly, and .s absolutely buried 
 under enormous accumulations of rocky fragments, consisting principally ot 
 very white limestone. They are from a few inches to several yards m dia- 
 meter and, at this place almost exclusively, contain the nondescript madre- 
 pore represented in PI. 28. Piles of these fragments, by the.r fissures and 
 interstices invested with thick moss, render the woods quite impassable. 
 
 • Those fires originate in lightning, or i.i the carelessness of Indians, and spread from the 
 .reat qua..tity of dry timber and leaves >>ith which the ground is strown. They are reqnenly 
 ^o extensive and numerons in s,.mmer, as to cloud the atmosphere as uith a fog. In the n.ght 1 
 have seen three or four large tracts red .i(h a smouldering flame, which, as the trees fall shoots 
 „p in fiery columns far into the sky. The noise of the falling of the trees, and the crackhng of 
 the timber, is heard at a great distance. 
 
Dr. Hi(i«BY on the Gcoscmpirt/ and (ieolosri/ of LaJw Huron. 179 
 
 Opposite the centre of the hurbour, und beliimi the vil!iij;e, ut a short di- 
 stance, 18 an eminence culled Blockhouse hill, which has the form of an em- 
 bankment, and is composed of sand atul rolled pebbles of various rocks 
 
 There is a aen 
 
 tic ascent from the water's edj^e to the distajice of from Ji<M) 
 (i) jOO yards. A sadden rise of from riO to .'JO feet then takes place at an anj^le 
 of (i.y, forming the bluff in (luestion, which presents to the west a front IjO 
 yards broad, and then retires, widening on either side, until after some yards 
 it is lost in the generally increased height of the ground. Its base is strown 
 with masses of primitive rocks, and its sun)iiiit is covered with largo slabs of 
 tlu limestone of the island. Nothing can be more harsh and desolate than 
 the aspect of this staticm on a near inspection. The village itself is encum- 
 bered with debris of rocks, so numerous and sharp-edged as to render talk- 
 ing very difficult. The sterile vicinity is bristled with black stumps and half- 
 consumed pines*. 
 
 At the bottom of a large cul-de-sac in Collier's Harbour, a narrow stream, 
 which falls from a small height in the Lake, communicates with a chain of 
 small lakes running into the interior of the island. The first of these is a 
 mile long, half a mile broad, and is surrounded by a dense forest, growing 
 among reeds and rushes. To the east of this is an opening leading to a se- 
 cond lake, and that to a third. 
 
 Drummond Island is separated from the Little Manitou by the False Detour, 
 a strait so called from its being freciuently mistaken for the True. It is from 
 8 to 10 n»iles long, and its greatest breadth is from 3 to G miles. Its depth in 
 the middle is seldom less than from 30 to 40 fathoms. As you enter it from the 
 south the opening is spacious and bold, with three fine capes on the west, and 
 one on the east. On the angle of Little Manitou is a shoal, with a mass of 
 while rocks in the centre : a short way within the strait, close to the last island, 
 are three low marshy isles crowded together. At the northern outlet the 
 shores are very rounded, with precipices on the west, and woody steeps to the 
 east In front is the open lake, studded with a few islets in pairs, and termi- 
 nated in the distance by the mis-shapen hills of the northern mam. On the 
 north-west is a blue waving line of the heights of St. Joseph, and on the 
 north-east the looming of the isles about La Cloche is just visible. 
 
 Little Manitou observes an eastern course. It is of a rounded form, with 
 a diameter of 7 or 8 miles. Its features are the same as those ot Drummond 
 but it is perhaps higher. Frequent conflagrations have destroyed almost ail 
 
 * In 1820 this past only escaped destruction, by a fire spreading from the woods, thro»si> the 
 Sr<at exertions of the inhabitants and a body of Indians. 
 
 '£" 
 
180 Dr. UiGMBY on the Geography/ and Gcolofri/ of ImUv Huron. 
 
 the well-Riown timber (still leavin,i? m\xxo uncomiuonly lHrf.r licml..(k), and 
 have expoHcd the asccndiiif-- hides ..fthc island in many phues. The shores 
 are hmded uith suecessive banks or stairs of small debris, and have here and 
 there terraces of limestone in situ. Mounting upwards, tlie ground is rugj^ed 
 with protrudinf? strata and rolled primitive masses ; and not unfre(piently in- 
 tersected by short ledftcs, which often crown the greatest height., atVordmga 
 table-land of small extent, and better wooded than the surface below, which is 
 only sprinkled with very young poplar-, birch-, and cherry-trees. 
 
 There i» a convenient harbour on the north side in the second bay from the 
 Third Detour It is a deep oblong indentation in this bay, and itself contauw 
 an inner eve. It is a (,uarter of a n.ile broad. The ship entrance is narrowed 
 to a few yards by a shoal that runs from the east angle two-thirds across. 
 
 Within this bar a vessel may ride with from 9 to 12 feet water ni tolerably 
 roon.y anchorage, the depth decrcasir.g gradually towards the botton. of the 
 
 indentation. , -i i \ a 
 
 The third detour, between Little and Grand Manitou, .s 8 mdes long by 4 
 broad, with high shores, and clear at both outlets. Off the south-east end of 
 the Little Manitou is a very extensive but easily distinguished shoal. - 
 
 The Grand Manitou may be estimated at 75 miles long, and 8 mdes broad 
 on the average. About its middle it is 25 miles broad, and at two places to 
 the west of the widest part, the shores are so deeply indented as nearly to 
 divide the island, only narrow morasses intervening between opposite bays. 
 
 The general characters of the Grand Manitou are the same as those ot 
 Drummond, but on a larger scale. It is higher, abounds more in precipices, 
 and is more rugged throughout *. At the western end it is of more majestic 
 features than any of the country which 1 have seen in other parts of Lake 
 Huron At the north end of the Third Detour, its shores are lined with 
 ranges of shingle, supported behind by an ascending country of woods.- 
 Toward the centre of this strait, ledges and low precipices begin to appear 
 along the beach, and soon rise to the height of 250 feet, crowned with cedar 
 and pine These ledges either rise perpendicularly, or are formed ot enor- 
 mous piles of displaced masses, from 7 to 10 yards in diameter, sloping at a 
 hi"h angle. These blocks advance into the water, and afford a hazardous 
 paUi over their slippery sides, under arches and through winding passages. 
 Within half a mile of the south-east angle of the Detour, a bluff precipice 
 40 feet high protrudes into the water, skirted by very large cubic masses of 
 rock. Of such masses, resting precisely on one another, the bluff itself is 
 * The above particulars I learnt from my friend and companion, Lieut. John Grant, R.N.; 
 having myself only visited the western end of the island. 
 
 \ 
 
 « 
 
\ 
 
 Dr. IJiGHBY on llic (ii'oprrapin/ and (linlotri/ of ImKc Huron. IRI 
 
 composed; mo thut the Numiuit, uith much of the laud hcluud, is a plutlnrm of 
 naked rock. Oi t <>•' iIk'hc natural Icnaces, knolls of lh)\vcrin^; slirubs and 
 chimps of trees arise. Uehind them \* the dense j-ioom of imponetrahle woods. 
 
 Of tlic strait which divides the (iraiid Manitou from the northern main 
 I possess no hiformation further than wl)al lias been stated. At a lime when 
 the Manitonlincs were (juite unexplored, I sailed throu^li the strait witln.ut 
 distinsuishinff it from the nunterous passes in that labyrinth of islands. It has 
 now undergone two surveys. 
 
 The strait which divides the (iraud from the Tourth Manitou on the north 
 h only one mile broad ; but on the average a league. It has been very seldom 
 
 visited. 
 
 Of the Fourth Mi nitou little is known. It is narrow, and of about one 
 third the size of the Little Manitou ; its long diameter crossing the direc 
 tion of the Munitouline chain. The shores arc much indented, and atVord 
 a very convenient harbour on its eastern side, which was used in 1821 by Ills 
 Majesty's schooner Confiance, Lieut. (Jrant. 
 
 The fifth and easternmost strait between the Povrlh Manitou and Cabofs 
 Head is 14 miles broad, and contains many shoals and islands, of which the 
 largest is appropriately named the Isle of Coves. 
 
 The island on >vhich are those singularly shaped rocks called the Flower- 
 pots, has long attracted notice. Accounts differ respecting its precise situ- 
 ation ; but it lies probably about 6 miles S.S.E. of the Fourth Manitou. The 
 Flower-pots are several insulated rocks, the greatest 47 feet high, consisting 
 of large tabular masses, placed horizontally one upon the other, and broad at 
 the summit, but narrow below. They stand on a floor of rock projecting into 
 the lake from the lofty island which bears their name. 
 
 Cabot's Head, a singular headland, is evidently a continuation of the Mani- 
 touline ridge. It lies 144 miles almost due north of St. Clair. It faces north 
 for about 25 miles, and then passes off to the south and east. It consists of 
 much indented limestone bluffs, rising occasionally to the height of 300 feet, 
 and skirled by numerous reefs and islets. On the western side of the head- 
 land, and to the south of it, the first 64 miles of coast display a range of cal- 
 careous precipices. A little to the north-east of Cape Hurd, the western ex- 
 tremity of Cabot's Head, one of the curvatures of the cliff forms a cul-de-sac, 
 800 yards long and 80 broad, having 7 fathoms water. It thus affords an 
 useful haven in this intricate part of the lake. 
 
 In addition to these remarks on the southern extremity of the Manitouline 
 chain, I have only to notice its generally increased elevation in this part of the 
 main, and in the neighbouring isles. 
 
i 
 
 IS2 Dr. BiGSBY on the Geography and Geology of Lake Huron. 
 
 Havinj«' completed my geographical observations on the Manitoulines, I shall 
 now proceed to describe the three principal divisions of Lake Huron. 
 
 The north-west arm of Lake Huron, wliich communicates with Lake Su- 
 perior, is of an oblong shape, the two longer sides at their western extre^iities 
 converging towards the north. It contains about 400 square miles, and is 
 crowded with islands of all magnitudes. The principal of these is St. Joseph. 
 It is 65 miles in circumference; and, together with the large Sugar Island, is 
 wedged into the end of the channel from Lake Superior, scarcely allowing at 
 the narrowest points the breadth of a mile to the rim of the three outlets front 
 Lake George. 
 
 St. Joseph is somewhat triangular in its form, its north and east sides meet- 
 ing almost at right angles. 
 
 Although an undulating ridge called the Highlands of St. Joseph, about 
 500 feet high, is foun^' throughout the island at the distance of a few miles 
 from the lake, yet the surface is not so broken as that of the Manitoulines ; and 
 he whole is better wr -ded. It has few or no precipices, but it is singularly 
 loaded with the debris of foreign rocks. Its southern point, a picturesque 
 cleared mound, once the site of a military post called Port St. Joseph, and 
 lately occupied by the British garrison at Collier's Harbour for pasturage, is 
 only six miles tiom Drummond. The north-west point of the island is 26 
 miles from this mound, in long. 84° and lat. 46° 18'; and the eastern an ,!« 
 lies about 18 miles north-north-east of it by the ship's course. 
 
 The waters on the north, west, and south -west of St. Joseph have received 
 distinct appellations That on the south, bounded also by Drummond, is a 
 large irregularly shaped archipelago, containing sixty-one islands and many 
 shoals. 
 
 The part ot I^ake Huron included between the north-east shore of St. Jo- 
 seph and the contiguous main, is called the Channel of Pelletau, from the 
 name Oi" a solitary Canadian residing on an isle at its east end. Except towards 
 the western extremity, this channel is almost a clear sheet of water, from 10 to 
 12 miles long, 6 niiles broad at the east end, and about a mile and a half at 
 the west. On the two sides of this channel the aspect of the country is very 
 different. On the south, the verdant acclivities of St. Joseph ar^ trending to 
 the north-west in two large bays. On the north are the black and denuded 
 fastnesses of the main laud ; an assemblage of greenstone mounds, swamps, 
 and ponds; with the margin of the lake fringed with reefs and rocky islets. 
 
 Near the west end, Pelletau's Channel widens into an expanse of 25 square 
 miles, and becomes full of islands, three of which are much larger than the 
 rest; and ^f these the largest is high, compact, and woody, and nearly blocks 
 
Dr. BiGSBY on the Geography and Geology of Lake Huron. 
 
 183 
 
 up tho lower entrance of the Narrows. The two others are at the north-east 
 angle of this dilatation, close to the main, with which tiiey form an admirable 
 haven lately selected by the Governor-general of British North America as 
 a military position by the name of Portlock Harbour. It is remarkable for 
 fiae scenery. While in Pelletau's Channel, as you approach the harbour, 
 at the distance of a mile or so, there is perceived an opening or break in a 
 high country, expanding as it is neared, and finally disclosing an extensive 
 haven interspersed with rocky islets, and girt by heights starting forth in a 
 aeries of woody or rocky capes: the whole is supported in the rear by three 
 ridges of hills covered with poplar, birch, and half-consumed pines. 
 
 The Narrows or Strait, at the upper end of the Channel of Pelletau, is one 
 of the three outlets from Lake George which may be considered as forming 
 the north-west limits of Lake Huron, since it there begins to be the seat of 
 currents, and of contracted dimensions. This strait is formed by the approach 
 of St Joseph to within two thirds of a mile of the northern main. This is the 
 extreme contraction, and occurs at the western end ; at the east the width is 
 almost a mile and a half. The length of the strait is 2 miles. The mam .s 
 a line of dark and lofty precipices. This part of St. Joseph is marshy 
 
 The small space constituting the Narrows contains eighteen islands ; those 
 near the main partaking of its sterile and forbidding character, and sometimes 
 being divided from each other by mural passages only a few feet across. 
 From the summit of the adjoining main is presented a truly scenic and striking 
 combination of high and sombre rocks, scantily clad with pine and oversha- 
 dowing a labyrinth of waters. As the islets approach St. Joseph, they become 
 low and woody, with marshy coves and shallow currents in their intervals. 
 
 A current prevails in the Narrows, but weak and inconstant. It is strong 
 at their western aperture, and is perhaps sensible throughout the basin into 
 
 which it leads. 
 
 The Narrows have considerable but various depth. At the east end, near 
 an excellent harbour, the lead indicated a depth of 42 feet, and being re- 
 moved a yard or so gave 96 feet. , ., , . 
 
 The second outlet from the Rapids to Lake Superior is the strait between 
 St Joseph and Sugar Island, called the Middle Passage, which terminates at 
 the lower end in Muddy Lake. It is from 8 to 10 miles long, having nearly a 
 southerly direction, and about 1 mile broad ; but it is contracted to one fourth 
 of that width at the lower end. The current is seldom half a mile per hour. 
 
 The Lesser or south-western Nibish Rapid completes the number of the 
 channels that lead to Lake Superior. It is contained by the western shore of 
 Sugar Island, and the southern or United States main. It occasionally ex- 
 
 VOL. VI. * " 
 
9 
 
 1st 
 
 184 Dr. BiGSBY on the Geography/ and Geology of Lake Huron. 
 
 t 
 
 j)an(ls into basins^ but is usually very narrow. About three miles to the west 
 of Muddy Lake, it is not more than | of a mile broad, and has six or seven 
 ihlets crowded in it. It is very shallow. 
 
 Muddy Lake, bounding the south-west side of St. Joseph, is a fine sheet of 
 water, of irregular shape, 17 miles long, and varying from 2 to 7 in 
 breadth. It has received its name from the nature of its bottom. There is 
 one small isle at the upper end, and a large one called Isle a la Crosse at the 
 bottom, with two or three others. Its shores are deep embayments ending in 
 grassy marshes, especially on the south-east side. There are several shoals ; 
 one, having G^ feet water, at the foot of the Middle Passage ;• another some- 
 what to the south-west, and some dry rocks at the lower end of the lake. 
 Sugar Island and George Island, the former 20, the latter 12 miles long, are 
 the two principal islands west of St. Joseph in the water communication be- 
 tween Lake Huron and Lake Superior. The lower end of Sugar Island con- 
 stitutes the northern shore of Muddy Lake ; that of George Island terminates 
 in the Middle Nibish, and the north-west Nibish rapids. 
 
 The Nibish rapids, which are 4 miles long, or more, are separated from one 
 another by these two islands. The lesser or south-western rapid has been 
 already noticed as flowing between Sugar Island and the southern main. The 
 middle Nibish, distant one mile from the north-western point of St. Joseph, 
 divides George Island from Sugar Island, and empties itself principally 
 tluough the middle passage. The waters of the north-west and north or 
 Little Nibish pass off" on the northern side of St. Joseph by two basins of com- 
 paratively calm water, 3 and 5 miles long respectively, divided by an im- 
 perfect barrier of islands ; the lower basin discharging into the Narrows of 
 Pelletau. 
 
 The Nibish rapids terminate upwards in a large basin, 8 miles long, and 10 
 or 12 broad, called Lake George, containing, besides the upper portions of 
 Sugar and George Islands, a multitude of smaller ones. 
 
 The Straits of St. Mary, which unite Lake George to Lake Superior, are 
 17 miles long, and from | to i of a mile broad, and have very violent rapids at 
 a narrow marshy spot about 2 miles above Lake George. 
 
 The Michilimackinac, or south-west arm of Lake Huron, has never been 
 examined, or only by the military engineers of the United States, whose 
 labours have not hitherto been communicated to the public. It is connected 
 with Lake Michigan by the strait of Michilimackinac, from 8 to 1 1 miles 
 wide, and of insignificant length, as being formed only by two opposite pro- 
 •nontories. 
 
 Its south side presents no peculiarities, except a peninsula, called False 
 
 n 
 
Dr. BiGSBY on the Geography and Geology of Lake Huron. 183 
 
 Presquisle, 9 miles from the island of Michilimackinac. On its north lies Isle 
 Bois-blanc. 
 
 The north side is merely a succession of shingled points and reaches, with 
 a thickly wooded and marshy interior, traversed by several streams. 
 
 The island of Michilimackinac is midway from either main, close to the 
 strait of that name. It is 42 miles west of Drummond. It is a long oval about 
 9 miles in circumference. The ends are broken, crumbling or grassy ridges, 
 while the long sides are lofty precipices declining at each extremity, separated 
 from the lake by rather broad beaches, and picturesquely clothed with maple, 
 cedar and vines, except where projecting rocks show their white and craggy 
 peaks above the foliage. 
 
 The view into Lake Michigan from the Indian path which winds among 
 the coppice on the top of the south-west cliff, is particularly pleasing. The 
 land, at first closing on the water at the pretty hamlet of St. Ignace and its 
 corresponding headland, at once dilates into a spacious sound with curving 
 shores and woody capes, and is interspersed in the extreme distance by clusters 
 
 of islands. 
 
 Tho cliffs of this island frequently break into shallow caves, which actually 
 perforate a projecting point near the south-east angle. Ks height (150 feet), 
 its whiteness contrasted with the dark shrubs, and the blue light streaming 
 through the aperture, afford a fine composition for the painter. 
 
 Excepting three small farms, little of the interior is cultivated : the heavy 
 timber has been felled ; and time has replaced it by flourishing underwood. 
 The surface is high and uneven, often marshy. 
 
 The town, consisting of from 100 to 120 decent wooden houses, is at the 
 southern end of the island, on the beach, under a crumbling ridge, on the edge 
 of whose summit is placed a small white fort. 
 
 On the south coast of Lake Huron, at about one third of the distance from 
 Michilimackinac to the Gulf of Saguina, there is an excellent harbour formed 
 chiefly by a peninsula. It is called Presquisle ; and is in lat. 45° 20' 39" ; 
 
 long. 83° 30' 13". 
 
 Little or no information is to be found in the writings of travellers respect- 
 ing the Gulf of Saguina. Batteaux, trading between Detroit and the lakes of 
 the west, pass down every summer as far as Traverse Island to avoid crossing 
 its boisterous mouth, where they would lose sight of land 
 
 This gulf and Thunder Bay are much larger than they are represented in 
 Smith's or Puray'!. map, and also in the one accompanying these notes ; but 
 as I have no documents for laying down this part of the lake with accuracy, I 
 have copied from preceding authors. 
 
 2b2 
 
186 Dr. BiGSBY on the Geography and Geology of Lake Huron. 
 
 Thunder Bay Islands and Middle Islands are flat, calcareous, and well 
 wooded. The lake, as I am informed by Major Delafield, for three quarters 
 of a mile east of Middle Island has only four feet water; indeed all the se- 
 condary islands of Lake Huron are surrounded by extensive spits and shal- 
 lows. 
 
 The shore from Point aux Barques to the river St. Clair forms a tolerably 
 straight line of beach with now and then a low cliff of clay. About midway, 
 a large block of white limestone rises from the waters of the lake, well known 
 to voyageurs by the name of Rocheblanche. 
 
 In describing the Manitouline Isles, I have already noticed Cabot's Head, 
 and the coast in its vicinity. 
 
 I have collected very few materials for the geography of the Georgian Bay. 
 It is now under survey by Lieut. Bayfield R.N., assisted by Midsh. Collins. 
 They report it to be crowded with islands and rocks. 
 
 Penetanguishene*, the British naval station in Lake Huron, is situated in an 
 inner bay of Gloucester Harbour. It is sheltered, as its name indicates, by 
 hills of sand and rolled blocks ; the coast and neighbouring islands being of 
 similar constitution for 30 miles round, but having a primitive base. 
 
 It remains now to add a few remarks on the rivers of Lake Huron. 
 
 The principal rivers are the Thessalon, Missassaga, French, Severn, St. 
 Clair, and Saguinaf . There are multitudes of smaller streams unmarked in 
 the map, which pour a brownish red water into the lake, and several of consi- 
 derable size to the east-south-east of Cabot's Head. 
 
 The river Thessalon flows into a deep bay on the north coast. It is 50 yards 
 wide at its mouth ; and in three or four miles becomes a mere creek. I have 
 noticed it because it is usually thought larger. 
 
 The river Missassaga at its entrance into the lake is § a mile wide, and 
 passes through a large swampy country, apparently alluvial. For five or six 
 miles the breadth rather increases as we proceed upwards. The current, 
 though usually sluggish, is at times rapid. Its borders are covered with long 
 grass and willows. Indians say that its source is a lake of the same name, 
 lying twenty days' journey to the north. 
 
 The French River from Lake Nipissing to Lake Huron, an interval of 75 
 miles, possesses peculiar characters. It less resembles one stream, than a con- 
 fused assemblage of rivers flowing, with frequent inosculations, among length- 
 ened ridges of rock. Its shores seldom present continuous lines, bounding a 
 
 * Long. 79° 35', lat. 44" 57'. 
 
 t There is another large one marked in the map in long. 82° 7', lat. 46" 10', or thereabouts. 
 I never heard of it. 
 
Dr. FiGSBY on the Geography and Geology of Lake Huron. 187 
 
 compact body of water, but are excavated with deep and narrow bays obscured 
 by high walls of rock and dwarf pines. 
 
 Its breadth therefore is variable ; sometimes extending more than a league, 
 and occupied by every diversity of island. 
 
 Few American prospects exceed in grandeur and singularity those which 
 are here afforded by groups of long and lofty islets, extending in giant rays 
 from a cenlre into some dark bay, the clear water reflecting their rugged 
 outlines and wild foliage, amid the solemn stillness pervading these ^ohtudes^ 
 
 Two cataracts occur. By one it leaves Lake Nipissing : the other is 20 
 miles below, and is called the Recollet. It is about 10 feet high and .s nar- 
 row. It is divided into three parts by two fragments of rock. The adjacent 
 red feldspathose eminences, and the black crags in the midst of the foaming 
 waters, beset with living and dead pine, impart great beauty to the scene. 
 
 There are many rapids; the most serious of which is that of Brisson re- 
 markable for its thirteen wooden crosses, commemorative of as many fatal 
 
 accidents. 
 
 The current is always strong ; perhaps 2 miles per hour. 
 The river Severn, about 25 miles long, and issuing from Lake Simcoe, is 1^ 
 mile broad at its mouth near Penetanguishene. It has two falls, and under- 
 goes a total descent of 80 feet from that lake*. 
 
 The St Clair is the only river of discharge possessed by Lakes Michigan, 
 Superior and Huron, which have a surface of 38i millions of acres, and are 
 fed by numerous rivers many times larger than the St. Clair, and issuing from 
 lakes of great dimensions. The evaporation must consequently be immense. 
 No hygrometric observations have yet been made. 
 
 The River St. Clair is 300 yards broad at its commencement. It flows 
 through a luxuriant alluvial country, with an average breadth of 1000 yards^ 
 It is 96 miles long; with a straight course and smooth and equable current of 
 about 2 miles per hour. At its head there is a rapid for f of a mile at the rate 
 of 5 miles per hour. It enters Lake St. Clair by a multitude of shallow change- 
 able mouths. , , TT 1 
 
 The River SaguX • ^as I am informed by the Rev. Mr. Hudson, missionary 
 to the Saguina Indians,) is 180 yards broad for 24 miles, flowing through a 
 level and heavily timbered district. It then divides itself into three small and 
 very circuitous branches, one of which is called Flint River. The River Sa- 
 guina is 120 miles from Detroit through the woods, and perhaps 220 by water. 
 
 * This calculation places Lake Simcoe more than 400 feet above Lake Ontario, distant 30 
 miles. The ascent is almost imperceptible, as I *m informed. 
 
 I I 
 
188 Dr. BiGSBY on the Geographi/ and Geology of Lake Huron. 
 
 Its neighbourhood has recently been surveyed, preparatory to sale by the Go- 
 vernment of the United States. 
 
 Sect. II. 
 
 ON THE GEOLOGY OF THE COUNTRY BORDERING ON 
 I.AKEIIURON. 
 
 § 1. 
 
 ON THE ROCKS IN SITU. 
 
 I will not apologize for the deficiencies that may be remarked, nor for the 
 inaccuracies that future observation may detect in the following pages. They 
 are in a manner natural to the efforts of a first observer in an unknown, vast, 
 and savage country. 
 
 The northern shore of Lake Huron, with its nearest isles, consists principally 
 of the older rocks ; the secondary occupy the rest of the lake. The primitive 
 rocks are part of a vast chain, of which the southern portion, extending pro- 
 bably uninterruptedly from the north and east of Lake Winnipeg*, passes 
 thence along the northern shores of Lakes Superior, Huron, and Simcoe, and 
 a fter forming the granitic barrier of the Thouraud Isles at the outlet of Lake 
 Ontario, spreads itself largely throughout the state of New York, and then 
 joins with the Alleghanies and their southern continuations. 
 
 The geology of that part of this primitive chain which borders on Lake 
 Huron is but imperfectly known. I shall give such detached information 
 concerning it as I am possessed of. 
 
 The French River flows over a granular gneiss at its source and mouth ; 
 and over red and feldspathic gneiss about the falls of the Recollet. Its shi- 
 vered and dislocated state, its mossy coating, and the astonishing quantity of 
 native debris prevented my ascertaining the direction of the strata, although 
 I landed more than once during my passage down the river. 
 
 The low and sandy beaches of the south shore of Lake Nipissing are 
 crowded with mounds of gneiss unmixed with any other rock. The direction, 
 from its great irregularity, I was unable to determine. 
 
 The rocks of the north coast, and its contiguous islands east from the French 
 River, consist of gneiss, with occasional mixture of hornblende f. 
 
 From the French River westwards to the islands of La Cloche, about 50 
 miles distant, the lake near the shore is studded with innumerable islets. In the 
 first 20 miles they commonly consist of gneiss, are barren, and surrounded by 
 shoals, and are often, in fact, a heap of ruins. This is particularly the case 
 
 * Vide Geological Transactions^ vol. v. Part II. page 607. 
 t Communicated to me by Lieut. Grant. 
 
Dr. BiGSBV on the Geograpki/ and Geology of Lake Huron. 189 
 
 very near the main ; but further out in the lake they are loftier, and sometimes 
 girded Nvith a belt of flat ground, richly wooded. This belt was in many 
 distances visibly supported on an horizontal dark slaty rock, which afterwards 
 proved to be shell limestone. The primitive rocks of these islands retained 
 their wonted sterility. Both the islands themselves, and most of the ridges of 
 which they are composed, have a south-west direction ; and individual masses 
 of gneiss were observed to dip either vertically or more or less to the south- 
 east ;— a coincidence in position with the gneiss of the whole valley of the St. 
 Lawrence, worthy of being remarked. 
 
 The Isles of La Cloche form a charming contrast to the bleak hills of the 
 main, in their forests and grassy vales, diversified, like an English park, by 
 clumps of fine trees. Some of them are composed, as I am informed (for I did 
 not see it), of a dark rock, which when struck sounds like a bell. 
 
 From La Cloche to the river Missassaga, a distance of 60 miles, la another 
 assemblage of isles ; but principally, 1 believe, within 6 miles of the shore. 
 In the first five leagues from La Cloche, they are woody, except those near 
 the shore, which are barren, and composed of gneiss. Landing here on the 
 main, I found issuing from a morass a round smooth mass (probably a vein). 
 50 yards broad, of crystalline quartz rock, running south-west, and containing 
 nests of silvery mica and galena. The former in some parts combming with 
 the rock, rendered it fibrous. 
 
 Twenty miles from La Cloche, and four from the main, is a chain of five 
 or more short islets, parallel to each other, and having their long diameter to 
 the north. They are composed of genuine granite ; and are bare, low, and 
 
 smooth. 
 
 Further to the west, soon after this, a multitude of small sterile islets, loaded 
 with debris, occur for 20 miles along the shore, composed chiefly of horn- 
 blende rock. They are of a deep black colour, and in one instance had the 
 glazed lustre occasional in this mineral. The rock varies in its constituents. 
 On the east it is moderately pure, but seldom very crystalline. Further west, 
 it takes a green tinge, and in certain spots feldspar or quartz is visible in 
 grains. It is often traversed by beautiful and strong veins of quartz, clouded 
 green and red. The compact black species contains much olivine, and some 
 elongated crystals of hornblende. 
 
 From hence to the river Missassaga, another appearance is noticed. The 
 islets of granite return, intermingling with the trap, both rocks being in the 
 form of low oblong smooth mounds ; the granite taking a northerly direction, 
 and the trap running south-west. Some of the islets possessed the calcareous 
 girdle before mentioned. 
 
190 Dr. BiGSBY on the Geography and Gcologi/ of Lake Huron. 
 
 Being delayed at a point 10 or 12 miles west of the Missassaga, for thirty-six 
 hours, I examined the beach of the mainland for one or two miles. 
 
 I here met, protruding from the woods into the lake, a rock, which is an 
 intermixture, on a large scale, of a light-coloured greenstone, and a compound 
 of white quartz and red feldspar minutely blended, but the latter predomi- 
 nating. These two aggregates mutually penetrate and traverse each other in 
 the most capricious forms (as in marbled paper). They are in equal quan- 
 tities; each being indicated by strongly contrasting configurations, knotty, 
 straight, waved, or stellular. Ramond compares the contortions and con- 
 fused appearances of certain rocks in the Pyrenees, to the effect produced by 
 a mixture of differently coloured glutinous liquors, issuing from separate ves- 
 sels at the same time, or to convolutions of smoke. These comparisons apply 
 well to the masses under consideration *. 
 
 These mounds exhibit no tendency to stratification; but their long diameter 
 appeared to be always directed to the north-west. They are found westward 
 for some miles near the shore, accompanied by a few granitic mounds, holding 
 a northern course. 
 
 The limits of this rock are not known. It is succeeded on the west by the 
 morasses about Thessalon river. It has given the name of Le Serpent to 
 that part of the north shore in which it occurs. Greenstone slate f, lying 
 beneath a granular quartz to be noticed hereafter, is found in one of the 
 islands forming the insular groups north of False Detour. The granular quartz 
 of Green Island is succeeded on the west, after a small interval of marsh, by 
 various greenstones, extending along the north side of the channel and nar- 
 rows of Pelletau. 
 
 At the lower end of the broad promontory constituting the east side of Port- 
 lock Harbour, and in the small isles on its east, the greenstone is dark and 
 compact, but here and there rendered slaty by weathering. It contains, in 
 patches, numerous masses of the red ingredient of the rock of Le Serpent, 
 from one to eighteen inches in diameter ; all bearing positive marks of attri- 
 tion to a moderate degree, and sometimes becoming so plentiful as to make the 
 rock a decided conglomerate. Proceeding still westwards, by degrees the red 
 ingredient disappears altogether, and the greenstone resembles a splintery 
 slate, commonly of a dark leaden hue, which runs however either rapidly or 
 gradually into cream-colour, red, blue, or light green. Its course is distinctly 
 
 * A somewhat similar rock appears to liave been found by Dr. MacCulloch in the Isle of Ar. 
 ran, not far from Glenleg. Vide Western Isles of Scotland, vol. ii. p. 399. 
 
 t The greenstone slate of the northern shore breaks, often, -with a very sharp edge and con- 
 choidal fracture. 
 
Dr. BiGSBY on the Geography and Geology of Lake Huron. 
 
 191 
 
 norih-west ; and it dips at a high angle to the north-east, when not absolutely 
 
 ''The greenstone of the large island close to Portlock Harbour varies much. 
 In one part it is nearly pure hornblende, splitting into cubic blocks ; m an- 
 other it gradually resumes its conglomerated state, the nodules be.ng small 
 and rare. At the south-west end it is very slaty for a square mile. 
 
 At the place where the hornblende abounds, thin waving vems ot hgni- 
 form asbestus are common. The centre only of the vein is pure, the sides 
 passing into greenstone. Vertical seams of quartz, with drusy cavities o 
 quartz crystals, are often met with ; and thready veins of galena also. 1 found 
 a mass of this ore loose, on the opposite side of this channel, we.ghn.g one 
 
 ^Th^prec^plts and steeps of the main in the Narrows of Pelletau are also 
 . greenstone ; but, as usual, of different aspects. The bluff at the lower end 
 fs only slightly slaty. It contains a confused mass of quartz vems, with a 
 mall quantity of copper pyrites., and the carbonate of that metal. The mid le 
 portion of these cliffs is extremely splintery, and appeals to be ferrug nous 
 At the head of the Narrows the greenstone is much less disintegrated, and 
 dips into the clear and deep waters in compact black walls. I have passed a 
 wle into the interior from the Narrows and Channel of Pelletau without 
 findinff any remarkable difference in geological structure between the interior 
 and the sliores. The contiguous islets are of a similar formation, and are 
 romnosed of aggregated ridges rising to a great height. 
 
 X" greensln'es dip fro^m the secondary strata on the south in the same 
 manner as at Malbay, 90 miles below Quebec, gneiss and mica-slate dip from, 
 Tnd abut against, a horizontal calcareous conglomerate full of organic remains, 
 and amonir others, of three species of orthoceratite. 
 
 Having now described, as far as my information extends, the primitive rocks 
 of Lake Huron, 1 proceed to notice the secondary rocks of the same d.s^ic 
 They are a portion of an immense basin, which, extending probab y without 
 interruption from the southern shore of Lake Winipeg, spreads U,elf over he 
 greater'part of Lakes Superior *, Huron, and Simcoe the whole of Lakes 
 Michigan, Erie, and Ontario, much of the western part of the state of Nev 
 York the whole of the states of Ohio, Illinois, Indiana, and Michigan, and 
 the rJst of the valley of the Mississipi. In describing the southern boundary 
 of the primitive chain, lave already traced the northern and eastern limits 
 
 . Dr. Wright, Inspector of Hospitals, has a specimen of chalk from the neighbourhood of 
 Lake Superior. 
 
 VOL. VI. "^ 
 
192 Dr. BiGSBY on the Geography and Geology of Lake Huron. 
 
 !ii 
 
 of the basin in question : its southern limits, qh far as I am aware, are only to 
 be found in the Gulf of Mexico, witli numerous interruptions, however, from 
 the older rocks in Pennsylvania, Virginia, Alabama, &c. On the west it is 
 bounded very irregularly by the primary districts that lie to the west of (he 
 Mississipi (from which it does not deviate fur), and to the south and west of 
 Lake Superior. The basin has been represented to extend as far westwards 
 as the rocky mountains ; but Mr. Schoolcraft has shown that the rugged coun- 
 try about the mouth of the Missouri consists of gneiss, with primitive lime- 
 stone intermixed ; and on further research, primary rocks will probably be 
 found still further southwards. 
 
 The connexion of the secondary with the primary rocks of Lake Huron has 
 been very imperfectly examined ; and, in fact, is almost wholly concealed by 
 the thick vegetation of those islets where the contact of the two fornuitions 
 does occur : or, in other cases, by the wide intervening tracts of wa(er. 
 
 I shall first notice those rocks, which, though not primary, possess less de- 
 cidedly a secondary character. 
 
 About the river Thessalon, on the large island opposite to, but seven miles 
 distant from, its mouth, and in the insular groups of the lake, north <»f False 
 Detour, my friend Major Delafield (American Agent under the 6th and 7th 
 Articles of the Treaty of Ghent) observed a granular quartz, forming the 
 north points of the islands, and dipping north, at an angle of 45°. On one 
 isle it was remarked to run imperceptibly into the greenstone slate that lay 
 beneath it. In High-cliff Island the granular quartz forms a precipice 100 feet 
 high. On this island limestone containing orthoceratites is met with, which 
 appeared to Major Delafield to alternate with the quartz. This quartz rock 
 is frequently seamed with white quartz, of which blocks, containing much 
 chlorite earth, lie loose on the shores. It is always hard, minutely granular, 
 and now and then very crystalline. It contains no petrifactions. 
 
 This rock extends westward as far as Green Island, and is then succeeded 
 by the greenstones on the north of the Channel of Pelletau. 
 
 Immediately on passing into the Lower Basin discharging into the Narrows 
 of Pelletau, a quartz rock shows itself obscurely among the marshes about 
 St. Joseph ; but from the insular barrier to Lake George, it is abundant, and 
 has a north-west course, and a dip which is either vertical or not discernibly 
 otherwise. At the barrier it consists of minute grains of vitreous quartz, 
 cemented by the same substance, rather powdery, opaque, and white. It is 
 somewhat easily frangible. Its fissures are sometimes lined with brilliant red 
 quartz crystals. 
 
 The islands on the north of the Upper Basin, about the Narrows of Pelle- 
 
Dr. BiGSBY on the Geographij and Geology of Lake Huron. 193 
 
 tau. nre of the same rock, with the same direction, but possessing more com- 
 pac'tness. At the foot of Lake (Jeorge it is often crystalline, dense, slightlv 
 translucent at the edges, conchoidal in fracture, but frequently also foliated ; 
 the fragments then becoming schistose, with a shining lustre. It is here very 
 commonly a conglomerate rock, of great beauty, studded with nodules of red 
 and brown jasper, averaging an inch in diameter, and usually arranging them- 
 selves in the form of belts or stripes, from one to five feet in breadth. Black 
 and brown liujmatite occur sparingly at this place. 
 
 Two broad strata of greenstone occur in this rock, three miles apart ; the 
 lowest five miles from the Narrows, whose rock it resembles, though it is more 
 syenitic. 
 
 The character of the sandstone, which I am now about to describe, appears 
 both in the position of the strata and in the texture of the rock itself, to be de- 
 cidedly different from the preceding. 
 
 The greater part of Lake George, as well as of the Straits of St. Mary, 
 rests (I believe) on a horizontal red sandstone. I have observed in various 
 parts of this lake, large slabs >)f this rock, with sharp fresh edges, most of it 
 soft, and of dull lustre ; but frequently quite crystalline, and remarkably hard, 
 and white with large ferruginous red spots. 
 
 Coasting the northern shore of Lake Goorge, towards dusk, in a canoe. 
 I fell in with a number of islets, with cliffs of brownish horizontal sandstone 
 strata, breaking into parallelopipeds. At the portage of the Falls of St. Mary, 
 this rock prevails in situ, especially in the half-inundated islets surroundmg 
 
 the Rapids. 
 
 It is in horizontal layers, eighteen inches thick. It is soft, splits readily, 
 and its principal colours are red, brown, or dull white, with frequent spots or 
 
 circlets of yellow. 
 
 The sandstone is environed by morasses, but re-appears largely on the 
 south side of Lake Superior ; and an active search would perhaps discover it 
 in situ near Michilimackinac, where I have seen much of its debris, and 
 where there is gypsum. 
 
 The shores of the main and islands near Michilimackinac present, for the 
 most part, only beaches of shingle, and rarely afford traces of rocks in situ. 
 At the Isles of St. Martin, however, we find a large deposit of gypsum. It is 
 an extensive bed, of the granular kind, white, gray, and brown, interspersed 
 with frequent masses of red, white, and brown selenite, occurring in shapeless 
 lumps, in veins, or in small and very thin tables, having three or more sides, 
 and sharp angles. 
 
 The horizontal sandstone, above described, in its general characters, and 
 
 2c2 
 
 i 
 
194 Dr. HujsHY on ilic (ko^raphif and Gvolo^i/ of ImIh Huron. 
 
 in Its' UHsoriutioii with gypsum, it* tloscly ullied to the red imul of I'iH{^lish geo- 
 logists, and to the ohl retl sundHtone of Werner ; and in these partindurs it 
 agrees with the Handhtunc of the (ienesee, in the state of New York, pro- 
 nomued to he tlie old red sandstone of Werner by the very eminent Marlure. 
 
 Connected probably with the horizontal sandstone are the caUareons rocks 
 of the island of Michilimackinac. Their character is well developed at the end 
 of the north-east clifl', adjacent io the fort. At the lop of the clilV a few hori- 
 zontal strata, very thin, white, and soft, appear: but immediately below, the 
 limestone loses the appearance of stratification, and becomes yellow and 
 ragged. The te.xture of mnch of it is compact ; but it is more usually vesi- 
 cular (as if from bubbles of air), the sides of the vesicles being encrusted 
 with crystals of quartz, in botryoidal clusters. A few of these vesicles are 
 3 or 4 feet in diameter, and contain several series of sntaller cavities. About 
 the middle of the western side of the island there is a cave, about 7 feet deep, 
 formed by the conlluence of several of these bowl-shaped hollows or vesicles, 
 wliose interior is here also subdivided into smaller cavities. 
 
 Other parts of the limestcne, contiguous to the vesicular, are an aggregate 
 of short angular fragments of slaty limestone and broken flints, in the greatest 
 disorder, the interstices being empty, and lined with quartzose crystallizations. 
 The fragments are from 1 to 8 inches in diameter, and they also are of an 
 ochry yellow colour. The vesicular limestone and the breccia are nearly equal 
 in quantity. 
 
 The bottom of the cliff consists of horizontal and moderately thick strata of 
 limestone-slate, of a white or blueish-white colour, very soft — so much so a§ 
 even to write. In some parts of the island the limestone contains a few Wut 
 and white striped flints. The limestone-slate forms the floor of ti..j !a!it! for 
 miles around, and in some part of the island or other may be found at every 
 level. After a careful search, I met with no organic remains in this limestone. 
 A friend met with a single bivalve, which may have come, however, from a 
 distance, as I observed iw \\m isle several loose fragments, bearing the inci- 
 sions observed in the n v- .nr vf the Little Manitou. 
 
 The cavernous and hj occiated limestone of Michilimackinac seems to be 
 allied to the magnesian breccia, which, at Bristol and in other parts of England, 
 is connected with the red marl. I have stated that this limestone is probably 
 connected with the red horizontal sandstone of Lake George. My reasons 
 for being of this opinion, independent of those founded on the local proximity 
 of the two formations, are, that in all the other lakes, and in Lower Canada, 
 throughout the whole of the valley of the St. Lawrence, in the lake and terri- 
 tory of Michigan, and in the Illinois, similar beds of horizontal sandstone, sup- 
 
Dr. BiuHBY .^M the Gcographj/ and Gvology of Lake lluion. 
 
 195 
 
 porting beilH of horizontal limestone, are found to be the excluMve and protlo- 
 
 minatinf^ rockH. 
 
 The remaining Hccondary beds, which I have to dcHcribc, are oaharcouM. 
 1 shall divide them into two Bpccies — the limcstn .e of St, Joseph and the 
 isles on tlie northern Hhorc, and tlie iimeslone ..f the Manitoniines ; nol in- 
 tending thereby to decide that tliey belong to formations essentially dilVeient. 
 but only to distinguish the one from the other, by reason of tiieir dilVerence in 
 character, in organic remains, and in geographical position. 
 
 The limestone of St. Joseph and the northern isles, is, wherever I have 
 examined it, horizontal. It occurs usually in weathered rrinnbling ledges, 
 seldom exceeding six feet in height ; or it floors the beaches in broken pave- 
 ments, advancing far into the shallow waters. 
 
 This species assumes various a.spects in distant parts of the same level; but 
 it is most commonly of different shades of brown and green. It is earthy, 
 
 rather soft, knotty and slaty. 
 
 In the Channel of Pelletau it is granular, passing into compact, and then 
 diflers little in hand specimens fiom the Dudley Rock in Staflbrdshire; having, 
 like it, much disseminated calcspar. 
 
 In this channel, and in the isles near St. Josepb, it is frecpiently an aggre- 
 gate of microscopic globules, opaque, and of a Dutch-green colour, mixing in 
 spots with limestone of the granular or crystalline texture. In the Narrows, 
 this oolitic species presents translucent nodule.s, less than a pin's head, which 
 I believe to be quartz ; especially as a quartzose conglomerate is immediately 
 at hand. On Green Island the green colour is often very strong ; and the 
 stratum contains a number of brown oblong nodules, as large as millet-seeds. 
 The rock rests upon a blackish-brown limestone-slate, seen only under v\ater, 
 and as truly schistose as that of Niagara. 
 
 The limestone of Thessahm Isle, in which the new species of orthoceratite 
 (PI. XXV. fig. 1, 2, 3) is found, is decidedly magnesian ; and in the compact 
 parts of it has the saccharoid texture belonging to dolomite. Its cavities, and 
 those of the organic remains, are lined with primitive rhomboids of the triple 
 carbonate of lime and magnesia. 
 
 There is little doubt but that the secondary bells of the primitive rocks in 
 the islets about La Cloche and the French River, are of the St. Joseph species 
 of limestone. The limestone here lies in horizontal beds ; it is much darker 
 than that of St. Joseph. Its texture internally is firm ; but it crumbles into 
 knotty flakes. I only observed bivalves in it. but others have seen oithocera- 
 tites in some of the westernmost of the isles*. 
 
 • The occurrence of similar belts of secondary strata, crowded with organic remains, and rest. 
 
196 Dr. BiGSBY on the Geography and Geology of Lake Huron. 
 
 Rhomboidal pearlspar and dog-tooth calcspar are the only accidental mine- 
 rals I have met vvith in the limestone of St. Joseph. 
 
 This bed is rich in organic remains and some of them are new. Their sub- 
 stance is not silicified, but rer ins calcareous. 
 
 Wherever this limestone occurs, orthoceree are very abundant, lying heaped 
 thickly together ii. small patches through the rock ; so that when the surface 
 is exposed, innumerable sections of them are displayed. They are accompa- 
 nied by milleporae, madreporae, encrini, shells, &c. The orthocerae are never 
 entire upwards ; but it is by no means uncommon to find the lower termina- 
 tion complete, the chambers and the siphuncle extending regularly to the 
 bottom. They vary much, not only in their absolute size, but in their pro- 
 portions. They are seldom less than 2 inches broad at the larger end, and are 
 usually from 10 to 18 inches long. Some taper so imperceptibly, as in short 
 pieces to appear almost cylindrical ; and I have seen specimens only 3 inches 
 broad at the top, that were 4 feet long : generally, however, they are broader 
 in proportion to their length. Major Delafield and others have seen them 6 
 feet long. 
 
 f Their lower termination is either acute, as in the specimen, Plate XXVI. 
 fig. 5, from St. Joseph's; or round and obtuse, as in the specimens, PL XXVI. 
 fig. 3 and 6, from an island otf the northern shore, near Thessalon. 
 
 ing in undisturbed horizontality upon the older rocks, is common in both the Canadas. Thus, at 
 the Falls of Montmorenci, 7 miles below Quebec, gneiss dipping south-east, almost vertically, is 
 covered by horizontal layers of limestone breccia and limestone, the latter containing the Conu- 
 laria q-iadrisulcata of Sowerby, and, among other species of trilobitc, that figured in Plate IV. 
 fig. 5, 6, 7, 8, of the Mimoire sur les Crustacees Fossiles, by MM. Brongniart and Desmarest, 
 from specimens found at Llandeilo, and preserved in the Ashmole Museum at Oxford. 
 
 Limestone breccia reposes horizontally on highly inclined mica.slate at Malbay. Repeated in- 
 stances of the same kind are met with in the St. Lawrence among the Thousand Isles, the great 
 breach of Lake Ontario. Here bot.i sandstone and limestone in horizontal beds overlie gneiss, 
 the limestone being without organic remains, but having imbedded in it splendid masses of sulphate 
 of strontia. I have seen each rock in contact with the gneiss, in places 40 miles apart, but at the 
 same level. 
 
 A decidedly crystalline texture often prevails in the limestones of the Canadas, but rather in 
 the higher layeis than in the inferior ; and this crystalline limestone is universally crowded with 
 organic remains. Thus at the Falls of Montmorenci, and at Point auxTrembles, 30 miles above 
 Quebec, it is seen loaded with organic remains, and particularly with large pointed orthoceratites, 
 300 feet above the St. lawrence, capping a succession of horizontal beds of black d brown gra. 
 nular limestone, with few organic remains. At the Bridge of Jacques Cartier, and at the Falls of 
 the Chaudiere on the Ottawa, crystalline limestone is found in a similar position : it abounds at 
 the east end of Lake Ontario. The crystallization in these cases is genuine, and does not depend 
 on the presence of encrinitic remains ; the facets are rhomboidal. The limestone is fetid. 
 
 f Excepting figures 3, 6, and J 1, all the drawings are of the natural size. 
 
Dr. BiGSBY on the Geography and Geology of Lake Huron. 197 
 
 Their transverse section is more frequently oval than circular; but both 
 
 forms occur. 
 
 The column is divided into chambers from the top to tlie bottom by septa, 
 which are usually concave toward the larger end; but in three specimens, 
 which I am inclined to consider as orthocera, PI. XXVI. fig-. 3, 6, and II, 
 found by my friend David Thompson Esq. in the island above referred to, near 
 Thessalon, the septa are convex upwards. 
 
 The interval between the septa, or the depth of the chambers, is for the most 
 part either constant in the same individual, or diminishes toward the lower 
 part of the column ; but in two specimens (see PI. XXVI. fig. 3 and 9), the 
 former from the island near Thessalon, the latter from St. Joseph's, the deptli 
 of the chambers varies irregularly in different parts of the same column. In 
 different individuals of the same species, the greater the column the greater is 
 the depth of the chambers ; but in different individuals of different species, the 
 depth of chambers bears a variable proportion to the size of the column. In 
 one of the specimens above referred to, fig. 11, the column of which is five 
 inches broad, and diminishes rapidly, the chambers are very shallow and nu- 
 merous. Figures 3 and 3 are in the most usual proportion. 
 
 In some species the siphuncle is near the centre, in others near the circum- 
 ference ; and when eccentric, in those species that are oval, it is usually placed 
 in the shorter axis of the section. In the same species the diameter of the 
 siphuncle is in proportion to that of the column, but in different species the 
 proportion of the two diameters is very variable. In PI. XXVI. fig. 8 and 1, 
 t'le siphuncic is larger in comparison of the column, and in PI. XXVI. fig. 10 
 is smaller than is usual. 
 
 The siphuncle, longitudinally considered, is in some instances a continuous 
 tube, regularly tapering from the top to the bottom ; in others it is contracted 
 in its passage through the septa, and enlarged in the intervals between them 
 (see PI. XXVI. fig. 2), as in the O. cordiformis of gowerby. An orthoceratite 
 from Malbay has the same character. 
 
 In figure 7 there is the appearance of a small interior tube within the si- 
 phuncle. 
 
 In figures 1 and 8, where the siphuncle is large, there are peculiar mark- 
 ings at the upper end, which doubtlfess are connected with the organization 
 of that part. I have seen other instances of this in larger .specimens. 
 
 In fig. 6 the siphuncle is marked along the side by a series of broad arrow- 
 heads, pointed upwards, and diminishing as they descend. They are merely 
 superficial markings, corresponding in number with the chambers. This spe- 
 cimen is 5 inches broad at the top, and 13 inches long. 
 
198 Dr. BiGSBV on the Geography and Geology of Lake Huron. 
 
 Among the specimens that I have seen, are some which strongly resemble the 
 following species figured in Sowerby's Mineral Conchology : viz. O. flexuosa, 
 O. Steinhaueri, O. gig-antea, and .O. cordiformis. 
 
 In the magnesian limestone of Thessalon Island are found many casts of 
 orthocerffi of a conical form, with blunt Isemispherical terminations and con- 
 cave septa, resembling in their general external outline many of the known 
 species ; but having a siphunculus of a very remarkable structure, which 
 differs from any thing known respecting this part in any of the chambered 
 shells. PI. XXV. figures I, 2, 3, are drawings of different specimens of this 
 
 fossil. 
 
 The siphuncle is large, placed laterally, and has an enlargement in each 
 interval between the septa. A tube runs down the axis of the siphuncle, 
 to the sides of which, at the middle of each enlargement, it sends off, at 
 right angles to itself, a number of radii, in verticillations, like spokes from 
 the centre of a wheel. The radii appear to vary in number, and cannot be 
 accurately counted, owing to the state of their preservation, as they are co- 
 vered completely with small crystals of pearlspar. Their number, however, 
 is about 16. In those places whence the radii spring, the tube has enlarged 
 rings : between these rings are elevated longitudinal ridges leading to the radii. 
 The tube diminishes in size toward the lower end of the column ; but does 
 not always taper regularly, nor, in different specimens, to the same degree. 
 
 Small branched corals are common, and I have found retiperae and chain- 
 coral : turbinolisB of large size, and well preserved, are abundant. 
 
 Cylinders, slightly conical, perfectly smooth externally, from 1 to 2 inches 
 in diameter at the large end, and from 3 to 18 inches long, are frequently found 
 among the remains of orthocerae. I have not seen their terminations. They 
 consist, within, either of granular limestone, or of confusedly crystallized white 
 calcspar, not radiated as in belemnites. 
 
 Neither any root nor head of an encrinite has been found on Lake Huron, 
 nor, to my knowledge, in America. The columns of encrini are exceedingly 
 numerous in the limestone of St. Joseph and the north ; but they are without 
 
 lateral arms. 
 
 The Entrochus Isevis, annulatus, verrucosus, and prominens of Miller are 
 the most abundant. Their diameter is Ihe same as is usual in English speci- 
 mens, and their length from 8 to 14 inches. Several specimens are covered 
 with a coralline net-work. 
 
 Pentacrinites are common, but very small. The bivalves have not received 
 attention : terebratulaj are met with. Among the univalves, euomphali and 
 cirri have been found. 
 
Dr. BiGSBY on the Geography and Geology of Lake Huron. 199 
 
 Several new species of trilobite have been found at St. Joseph's, one of 
 which is represented in Plate XXVII. 
 
 I am obliged to Charles Stokes, Esq. for a communication respecting the 
 specimen fig. 1 : for which see the Appendix to this Paper, page 208. 
 
 The Manitouline limestone is separated on the west and north from that of 
 St. Joseph by waters, low woods, and morasses, nothing being visible near the 
 promontory of the True Detour for many miles around, on the shores of the 
 main, and of the neighbouring islands, but limestone-shingle, white, slaty, 
 and devoid of petrifactions. On the east the Manitouline limestone is con- 
 nected by a chain of high and rocky islets with Cabot's Head. I have seen 
 numerous specimens from both extremities of this ridge ; but it is with Drum- 
 mond. Little Manitou, and the west end of the Grand Manitou, that I am per- 
 sonally conversant. 
 
 Thick vegetation, debris, and the displacements usual in uncultivBted coun- 
 tries, prevent an accurate examination of the different successive beds of this 
 chain ; which are to be considered, however, as belonging to one formation, 
 —from their intimate geographical connexion, from their regular horizontal 
 position, and from their containing in distant parts of the chain the same or- 
 ganic remains : but, as is the case with secondary rocks in all parts of the 
 world, their character differs perpetually in places situated on the same level, 
 or even in juxta-position. This limestone is distinguished from that of bt. Jo- 
 seph and the north by its greater compactness and hardness, by the difference 
 of its organic remains, and by the silicified state in which they are found ; all 
 the fossils of Drummond being quartzose or chalcedonic, those of the Little 
 and the Grand Manitou, and of Cabot's Head and its vicinity, bemg less 
 
 purely so*. 
 
 This limestone rises usually to the height of 250 feet above the level of the 
 lake, rarely at once in one abrupt precipice, but oftener in confused stair-hke 
 
 led^'Cs. 
 
 The beach at Collier's Harbour in Drummond Island is in some parts 
 iloored with a brown, compact, hard limestone ; almost, if not entirely, devoid 
 of organic remains. It is massive : its surface is usually full of conical cavi- 
 ties, often confluent, about an inch in diameter, and from I to 6 inches deep. 
 Their interior occasionally contains a series of similar cavities. A very simi- 
 
 * The substance of the testaceous remains found about Cincinnatus, in the state of Ohio, in 
 parts of Lake Michigan, and in the route from that lake by the Wisconsin river to the M.ss.ss.p., 
 consists of fine white quartz. The cellular and chain madrepor.s, turbinoli*, tubipores, ret.pores, 
 and shells of the north-east .nd of Lake Erie, resemble those of Dudley in Staffordshire, and are 
 cherty. 
 
 VOL. VI. 4 D 
 
 I 
 
 I 
 
'^00 Dr. BiGSBY on the Geop^raphi/ and Geology of Lake Huron. 
 
 lar stratum occurs, at the level of the lake also, at the north-west end of the 
 Little Manitou, and at the south-west angle of the Grand Manitou. In the 
 Little Manitou it contains anomiae, which abound at the south-east angle of 
 the island. 
 
 On proceeding inland, at Collier's Harbour, at an elevation of 100 feet, we 
 find ledges of very hard quartzose white or light brown limestone, piercing 
 the sides oi" the slope, and finally, in somewhat slaty and squared blocks, con- 
 tributing to form Blockhouse Hill. The fractured surface of this rock sparkles 
 with what the frequent crystallizations in cavities and fissures show to be quartz. 
 It is in this neighbourhood that the nondescript madrepore hereafter to be 
 described is principally found. The angle of Drummond, on the north of the 
 False Detour, and part of the western end of the Grand Manitou, rise iu clitFs 
 250 feet high. The rock, in both cases, resembles the quartzose limestone of 
 Collier's Harbour. Major Delafield found the summit of the former to be a 
 platform, crowded with ammonites and anomise. The latter to judge from 
 its debris, contains the same organic remains as Blockhouse Hill. It abounds 
 with astreffi, and chain-coral, 2 or 3 yards in diameter. Its fissures are fre- 
 quently lined with honey-yellow talc-spar. To the south of Drummond is an 
 isle, almost wholly composed of iron pyrites, mixed with some brown calcare- 
 ous matter and quartz nodules. 
 
 In parts of the Little and of the Grand Manitou, the limestone on the shore 
 is of a blueish gray or light brown colour, verj finely granular, and extremely 
 slaty. It divides into small fragments no thicker than paper, which are ar- 
 ranged by the wave, edgeways, in undulating lines round the boulders on the 
 beach. I could not find in it any organic remains; but trilobites have been 
 met with in '^ rock so similar, found in loose fragments on the shores of Drum- 
 mond, that I believe them to occur imbedded in this limestone-slate. 
 
 Immediately above this slaty bed, or alternating with it, in both Manitous, 
 is a stratum, whrch occurs in thin broken patches, and is brown, and almost 
 black in parts. It is very soft, of coarse texture, and full of knots of all sizes. 
 These knots in the Little Manitou are very fetid, and often send oif several 
 short round branches. They often bear strong marks of cellular madrepore. 
 This is by no means so slaty as the contiguous bed. It abounds in organic 
 remains, some of which are peculiar to it : others are common to the Mani- 
 toulines. 
 
 In the middle of the north side of the Little Manitou, 30 miles east of Col- 
 lier's Harbour, and 100 feet above the level of the water, in low interrupted 
 cliffs, we find a dull-brown granular limestone, rather hard and slaty, fetid, 
 and free from shells. We have the same rock at the same level in the Grand 
 
Dr. BiGSBY on the Geography and Geology of Lake Huron. 201 
 
 Manitou ; but there it is not fetid. Specimens from Cabot's Head, the Flower- 
 pots, and the Fourth Manitou, resemble the fetid limestone of the Little Ma- 
 nitou : they are darker, coarser, very fetid, and abound in the petrifactions 
 common to this range. 
 
 The fissures and surfaces of the limestone strata of the Little Manitou are 
 marked by singular scarifications, not observed in any other part of Lake Hu- 
 ron. They are narrow and shallow, as if made with a penknife, and occur either 
 singly at hazard, or forming a multitude of parallel incisions, placed together 
 promiscuously. They crowd the surface of the rock and of the various or- 
 ganic remains. Their greatest length is an inch, their ordinary length much 
 less. Sometimes they are only punctures, of triangular, rhomboidal, oblong, 
 or semicircular shape. 
 
 On the south-western shore of Lake Huron, at Presquisle, the limestone is 
 only seen at the bottom of the harbour, forming a broken pavement, on a level 
 with the waters of the lake. It diifers little in appearance from the fetid lime- 
 stone of the Little Manitou, being brown, granular, and tolerably hard ; but 
 I did not ascertain its fetor. It contains the organic remains prevalent in the 
 limestone of the Manitoulines *. 
 
 The limestone of Middle Island resembles that of Presquisle, and is full of 
 
 organic remains. 
 
 The organic remains of the Manitouline limestone have been collected 
 principally in Drummond, and chiefly through the persevering exertions of 
 Mr. M. White of the Army Medical Staff. This island having been assigned 
 
 * I found at Presquisle a loose fragment of limestone, having the peculiar suture observed in 
 that of Kingston on Lake Ontario. This limestone is subdivided, not only by the horizontal 
 planes which render ' schistose, but by other planes which also are horizontal. The upper and 
 lower surfaces of these partitions are covered with a brown or black shining matter. They are 
 extremely rough, from their mutually sending fortu innumerable processes of the most irregular 
 shape, protruding from half an inch to 2^ inches, which are received into correspondin depres- 
 sions in the opposite surface. A section of the partition resembles the suture of the human cra- 
 nium: like which, the limestone suture can be taken asunder and replaced without fracture. 
 
 The nth stratum from above, at the Table Rock of the chasm of Niagara, is intersected 5 or 
 6 times in this manner. This suture has also been observed on Lake Erie, in white granular 
 limestone ; and in Lower Canada, at Point aux Trembles and Point Levi, in brown fetid crystal, 
 line limestone. It has been found also in ths river St. Clair, in loose fragments of black fetid cry. 
 
 stalline limestone. 
 
 At Point Levi, and in several of the strata at the great chasm of Niagara, it is very minute, 
 and leaves the horizontal direction, wandering about in the most fantastic curves. It often ex. 
 tends only to a little distance, and disappears as a very small fissure, coated with a thin black 
 scale. 
 
 2d2 
 
I 
 
 y 
 
 lU 
 
 202 Dr. BiGSBY on the Geography and Geology of Lake Huron. 
 
 by the Commissioners under the Treaty of Ghent, to the United States, the 
 British garrison will be withdrawn ; and as it will not be held as a military 
 post by its present owners, it will be long, probably, ere its fossils again be- 
 come the object of research. 
 
 The first of the organic remains which I shall describe, are some corals 
 found in the quartzose limestone at Collier's Harbour, and at the west end of 
 the Grand Manitou, differing from any that have yet been discovered in a 
 recent or fossil state. Their variations of external form are such as to have 
 led me to separate them into five species ; and as it is in that particular alone 
 that they differ, it is of one only, and that the most abundant, that 1 have given 
 a detailed description ; contenting myself, as to the rest, with pointing out 
 those changes of form which distinguish one species from another. The figures 
 are all of the natural size. 
 
 Species I. — The corals of the species represented in Plate XXVIII. fig. 2, 
 have in their general appearance a considerable resemblance to vertebrae. 
 They are columns, tapering from the top, composed of similarly formed joints, 
 which diminish downwards both in length and breadth, though not in regular 
 "•nidation. The length of each joint in this species is about an inch, and the 
 breadth exceeds the length. The transverse section is circular. The lower 
 and middle part of each joint is cylindrical, or slightly conical; the upper part 
 swells out, and is inflected inwards at the top, so as to meet entirely the base 
 of the joint next above it. This dilated part is, in different species, in very 
 variable proportion to the rest of the joint. The lower part of one joint is in- 
 serted, to some little depth, into the upper part of that next beneath it, so as 
 to attach the joints firmly to one another. The external surface is covered 
 over with a thin smooth coat ; but this is rarely preserved, and then only in 
 small portions. The surface is usually without this coat, and is then longitudi- 
 nally striated. 
 
 Where the joint is most dilated, a thin horizontal septum, formed by the 
 abrupt inflexion inwards, and coalescence of the upper and lower parts of the 
 tmter coat, passes transversely across the joint ; as is seen in two of the joints 
 
 in figure 2. 
 
 The section represented in fig. 6 shows the radiating lamellae peculiar to 
 madreporae, and the congenerous lamelliferous corals. These lamellas are lon- 
 gitudinally disposed, and radiating from the axis of the column to its parietes, 
 there form the external striae. 
 
 In the axis of the column is a hollow tube ; but the whole interior of the 
 column is in most specimens obliterated, being filled with dark granular lime- 
 
Dr. BiGSBY on the Geography/ and Geology of Lake Huron. 
 
 203 
 
 stone, or with quartz, having carious holes or cavities, lined with rock crystal. 
 The substance of the coral itself is silex, with a slight calcareous admixture. 
 Including all the species, I have seen sixty specimens of this fossil; but in no 
 instance has either the base of the attachment, or the upper extremity of the 
 column, been preserved. The greatest length of any column that I have seen 
 is 27 inches. The columns are not found in groups, but single, mixed with 
 
 turbinolite, chain-coral, encrinites, &c. 
 
 Species U PI XXVIII. fig. 1.— This species is the largest. The greatest 
 length that I have seen in any joint has been 1| in.; of which the diameter 
 at the base was If in. The greatest diameter I have seen at the base of any 
 joint, has been 2| in., the length of the joint being H in. The upper part ot 
 each joint is much less inflated in this than in the first species. 
 
 Suecie- III fig 3.-In this species, which is the smallest I have met with, 
 the column tapers more rapidly, the upper part of each joint is more enlarged, 
 and is greater in proportion to the rest of the joint, than in the two foregoing 
 
 ""^'^Spedes IV. fig. 4.-In this species the plane passing through the line of 
 the base of each joint, is oblique to the axis of the column. 
 
 Speeies V. fig. 5.-In this specie3 the cylindrical part of each joint disap- 
 pears, and the joint assumes the form of an oblate spheroid. 
 
 Many other species of coral are also met with in Drummond Island. 
 
 Of astre^ I have seen six or seven species, one of them considerably resem- 
 bling the lithostrotion of Llywd. 
 
 Of the genus Porites, or madreporse of Lamarck, one spec.es 
 
 Of Caryophyllia one species, which merits a more detailed notice. It is re- 
 presented ii PI. XXIX. figures 1 and 2. The former figure shows the 
 outside and the base of the coral, and exhibits a peculiarity which is quite 
 new, I believe, to corals of this genus. Tubes appear branching from the 
 outside, and communicating with the interior. Most of these are broken off; 
 but one of them remains, which is three-fourths of an inch long, and akes an 
 ascending direction. In fig. 3, tubes are seen near the base, which take the 
 contrary direction. It is difficult to imagine what purpose these branches could 
 serve in the former case ; but in the latter they might assist in strengthening 
 the base of attachment of the coral. I have in my possession a specimen 
 from Collier's Harbour, containing a group of eleven of these corals, closely 
 
 crowded together. , • • e 
 
 Turbinoliee abound in Drummond. The different species vary in size, rom 
 1 in. to 10 in. in length; the larger being sometimes 4 inches bioad at the 
 upper end. I have seen 21 of these corals in one mass, each 10 inches long. 
 
•t ■ ■■ 
 
 204 Dr. BiGSBY on the Geography and Geoiogi/ of Lake Huron. 
 
 One species, which is common, resembles that from Italy figured in Par- 
 kinson's Organic Remains, pi. iv. fig. 9. — Plate XXIX. fig. 3. represents the 
 smallest species. Figure 4 is remarkable for the spiral cui-vature around the 
 centre of the radiating lamellte. Other species are represented in figures 
 5 and 6. 
 
 The chain-coral (Tubipora catenula, Gmelin ; Catenipora escharoides, La- 
 marck) is common ; as also the Tubipora Strues, Park. Org-. Re7n. pi. ii. fig. I, 
 and Tubipora ramosa. Ibid. pi. iii. fig. 1. 
 
 Small retiporae, and milleporse, are abundant. 
 
 Of shells there are many species of terebratulse found near Collier's Har- 
 bour, and a large species is common near the True Detour, and in the cliffs 
 near the False Detour, where it is accompanied with ammonites. 
 
 Of orthocerae there are some remains; but they are not so abundant in 
 Drummond as in St. Joseph's or Thessalon Islands. Among them one spe- 
 cies has a considerable resemblance to O. annulata of Sowerby. PI. XXX. 
 figures I and 2, represent two fragments, which resemble those figured in 
 Hreynius's Dissertatio de Polythulamiis, tab. 6, fig. I and 2. 
 
 Another class of fossils from Collier's Harbour differs from any thing I have 
 seen. They are columns, usually tapering rapidly, composed of circular discs, 
 with rounded edges, placed one upon the other. Each disc is from ^ to |^ in. 
 thick, and from 5 to 2 in. in diameter. They vary much among themselves. 
 Thus PI. XXX. fig. 5, is of considerable length, and tapers very gradually. 
 In fig. 3 the diminution is rapid. In fig. 4 there is a sudden diminution fn m a 
 large to a small size. In fig. 6 the column is curved ; in fig. 7 the discs are 
 placed obliquely. 
 
 The entrochites mentioned among the organic remains cf St. Joseph and the 
 north occur in Drummond also, but sometimes of twice the size. The Penta- 
 crinite is also met with. 
 
 The Little Manitou, in addition to the turbinoliae, and most of the other 
 corals of Drummond Island, possesses several species of organic remains, 
 which are found no where else throughout the Manitouline chain. They 
 occur in the knotty stratum : but as they are but obscurely defined, I shall pass 
 them over. 
 
 On the Foreign and Native Debris of Lake Huron. 
 
 The shores and bed of Lake Huron appear to have been subjected to the 
 violent action of a flood of waters and floating substances rushing from the 
 north. That such a flood did happen is proved, not only by the abraded state 
 of the surface of the northern mainland and scattered isles of the Manitou- 
 
Dr. BiGSBY on the Geography and Geology of Lake Huron. 205 
 
 line range, but by the immense deposi ,8 of sand and rolled masses of rock 
 which are found in heaps at every level, both upon the conti..ent and islands : 
 and since these fragments are almost exclusively primitive, and can in some 
 instances be identified with the primitive rocks in situ upon the northern shore; 
 and since, moreover, the country to the south and west is secondary to a great 
 distance, the direction of this flood from the north seems to be well esta- 
 blished. 
 
 The boulders of granite, gneiss, mica-slate (rare), greenstone porphyry, 
 syenite, and various amygdaloids, are principally of such varieties of these 
 rocks as I have not met with in situ, either in the neighbourhood of Lake 
 Huron, or in a journey of 600 miles which I made to the east and north-east 
 of the lake, through the forests of the river Ottawa. 
 
 Of mica-slate I met with only two fragments, of a brown colour, among the 
 trap isles. A fragment of serpentine was found in Drummond, on Blockhouse 
 
 Hill. 
 
 The ffreenstone porphyries have a light-coloured base, and contain crystals 
 of red or white felspar — seldom of both in the same block. I have seen boul- 
 ders of the porphyry with red felspar, on the Ottawa, 500 miles to the east 
 of Lake Huron. The syenites are the same as those of Europe. 
 
 The amygdaloids are often coloured brown by iron, and then contain almond- 
 shaped masses of epidote only. The green varieties contain nodules of agate * 
 and red jasper, white amethyst, epidote radiating upon layers of quartz and 
 
 small garnets. 
 
 It can scarcely be doubted that these rocks will be found in situ somewhere 
 on the northern shore of Lake Huron, between the Missassaga and Pelletau's 
 Channel. It is there and on the Isle of St. Joseph that their boulders most 
 abound. Together with the fragments of the above-mentioned rocks, are 
 found others of trap, greenstone-slate, greenstone-conglomerate, jasper-con- 
 glomerate, and quartz rock. These occur in every part of the lake, but most 
 abundantly near their parent rocks. The conglomerates closely resemble 
 those which have been found on the northern shore in situ. The base of the 
 conglomerates is either quartz or greenstone. Of the quartzose conglomerate 
 the nodules consist rarely of white translucent quartz, sometimes of green- 
 stone ; and more commonly of red, green, brown, black, or parti-coloured 
 jasper. In some instances pieces of quartz— rarely of greenstone— are mixed 
 with those of jasper. The greenstone conglomerates contain nodules, either 
 
 * Agates, jaspers, &c. are found abundantly as pebbles, on Lake Superior and about the Mis- 
 sissipi. 
 
.1 •'■•. 
 
 '^06 Dr. BiGSBY on the Geography and Geologj/ of Lake Huron. 
 
 of quartz, of ffreenstone, or of the red ingredient found in the rock of Le 
 Serpent. This latter conglomerate has been noticed as occurring in a'Uu in 
 the Channel of Pelletau. 
 
 It is only about the Narrows of Pelletau that the rock of Le Serpent has 
 been seen in a rolled state. Breccias similar to the conglomerates are not un- 
 common ; but I have never found them in situ. 
 
 Pebbles of red sandstone, and quartzose or slaty limestone, have a very li- 
 mited range : they only now and then wander as far as the Manitoulines, the 
 southern shore, or Michilimackinac. 
 
 I have already noticed the quantity of primitive boulders found on the Isle 
 of St. Joseph. The beach of the rivers Thessalon and Missassaga is covered 
 by boulders of black trap, granite, gneiss, and jasper-conglomerate. 
 
 The Georgian or Penetanguishine arm of the lake is loaded to excess 
 with sand and rolled pebbles. Penetanguishine, and much of the south-east 
 coast of this arm of the lake, is a collection of sand-hills, enveloping quartzose, 
 granitic and amphibolic blocks of all sizes, and in vast quantity. 
 
 Passing into the southern division of the lake, 6^ miles south of Cabot's 
 Head, the limestone cliffs of the Manitouline range are succeeded by cUffs of 
 clay. From this point beds of clay, covered towards the upper part of the 
 river St. Clair by thick beds of sand, extend for 150 miles to Lake Erie, and 
 thence along the northern shore, which presents a series of clay cliffs and 
 sand-hills, to the north-eastern extremity of the lake. The whole of the in- 
 tervening shores and woods are strown with rolled blocks of gneiss, porphyry, 
 conglomerate, and greenstone, such as prevail on the northern shore of Lake 
 Huron. In a south-westerly direction, the clay-beds prevail over the Michi- 
 gan territory, and the states of Indiana and Illinois, to an unknown distance. 
 In (he two last-mentioned states (which I have not visited) rolled blocks 
 abound. 
 
 The argillaceous and sandy banks of the southern shore of Lake Huron 
 are conspicuous near Point aux Barques, in the Gulf of Saguina, and about 
 Presquisle. The debris of the rocks of the northern shore are here rare, and 
 much rolled.— Staurotide was picked up on the southern shore by Mr. School- 
 craft. 
 
 Besides the sand and boulders before spoken of, which are ancient, and 
 have travelled from a distance, there are fragments of another character, which 
 may be called native, reposing on the parent rock, or not far removed from it. 
 This debris is comparatively recent, having been detached by various natural 
 causes, such as torrents, change of temperature, &c. The latter agent ope- 
 rates either by the expansion and contraction of the rock itself, or of the water 
 
Dr. BiGsnY on the Gco^raphi/ and Geology of Lake Huron. 207 
 
 contained within its fissures. In (lie spring the nocturnal frosts and diurnal 
 thaws are very violent. In the winter the thermometer is fre(iuently 50° helow 
 the freezing- point, and in summer it ranges from 60° to 90° of Fahrenheit. 
 I once saw it at noon, on the 20th of June. 1820. at lOlf in the shade. 
 
 These recent fragments, whether of the older or newer rocks, are angular 
 and mostly small, and cover their parent rocks, as well in t»e high as in the low 
 grounds, often to the depth of several feet. E.xamples of this arc seen in the 
 slaty greenstone of the Narrows, in the quartzose limestone of Drummond, 
 and in the quartz rock at the foot of Lake George.— All the countries to the 
 north of Lake Huron are loaded with similar debris. The French river, in 
 one wild spot, the scene of an Indian massacre, is almost choked with it. In 
 Lake Nipissing, near its southern shore, there is a large heap of square clean 
 inasses of gneiss piled together promiscuously. 
 
 An instructive fact is presented by many parts of Lake Huron, and very 
 strikingly in the channels of Pelletau. It shows that the recent debris is nearly 
 stationary. The opposite shores of this channel consist of different rocks, 
 the one being limestone, the other greenstone. Each shore is lined with its 
 own debris, without any admixture, except that of rolled pebbles of granite, 
 pudding-stone, or greenstone, left by the debacle on the calcareous beach. 
 
 In the spring the ice occasionally removes fragments of great size : the in- 
 habitants of Quebec annually see them transported in this manner down the 
 St Lawrence During the winter the ice surrounds the blocks that are upon 
 the shallows ; and on being broken up in May, it carries them by a rise of 
 water to some other shore. Remarkable instances of this are found on the 
 islets near the south end of St. Joseph ; where, a few yards from the water, 
 and a little above its level, rolled stones, many feet in diameter, are found de- 
 posited, with a furrow extending from the water to their present place ot rest. 
 That changes in the level of Lake Huron have occurred, and that its surtace 
 once stood much higher than at present, is proved by the traces of ancient 
 beaches and zones of rolled stones and sand that are found m the neighbour- 
 hood of the lake. Such an occurrence has been noticed in Collier's Harbour 
 at Blockhouse Hill, which has the appearance of a beach, and of having formed 
 the west end of the Isle of Drummond, when the lake stood higher than a 
 present. Similar alluvial ridges are found surrounding the other lakes and 
 rivers in Canada. These may be accounted for partially by the effects of the 
 wind ; which, blowing strongly from certain quarters for a few days, accumu- 
 lates the water on the leeward coast, the waves there washing up tn<^ shingle 
 in scalar ridges to the height of 6, 8, or 10 feet. 
 
 On concluding this Memoir, I have to express my grateful acknowledge- 
 
 VOL. VI. ^ ^ 
 
208 Dr. BiGSBY on the Geography/ and Geology of Lake Huron. 
 
 mente to Sir James Macgregor, and to Dr. Wright (Inspector of HoHpilalH), 
 for their zealous aid, aft'ordcd to me when prosecuting tliese rcHearches.— 
 Mr. M. White of the Army Medical StatV will also accept of my best thanks 
 for various acts of kindness. Mr. Parkinson and Mr. C. Stokes have most 
 obligingly given me free access to their libraries and collections. 
 
 APPENDIX. 
 
 I. On a Tr'dobitc from Lake Huron. 
 
 BY CHARLES ST0K.ES, ESVI. 
 
 " In breaking away the rock from a specimen of trilobite found at St. Jo- 
 seph and now in my possession, a fortunate fracture exposed a small part of 
 «he underside of the fossil; and encouraged me, as the rock was of a favour- 
 able texture, and the fossil in a good state of preservation, to attempt a further 
 dissection, in the hope of laying open some parts of the animal with which we 
 have hitherto been unacquainted ; and I discovered the part forming the en- 
 trance into the stomach. Its structure, which considerably resembles that of 
 the analogous parts in some recent crabs, will be best explained by the accom- 
 panying drawing (PI. XXVII. fig. 1. b.) I have frequently attempted to cut 
 away the rock from specimens of trilobite from Dudley ; but owing to its hard- 
 ness, 1 have not yet succeeded in developing any thing similar." 
 
 II. List of some of the Recent Shells of Lake Huron. 
 1 am obliged to I. E. Gray, Esq. of Burton-street, Burton Crescent, for the 
 names of some recent shells which I collected in Lake Huron. 
 
 Helix albolabris, . . 
 
 alternata, . . 
 
 angulata ? 
 
 Planorbis trivalva, . . 
 Lymnaea Catascopium, 
 
 heterostropha, 
 
 (Nov. Spec.) 
 
 Physa (Nov. Spec.) 
 Valvata (Nov. Spec.) 
 Cyclostoma tricarinta, 
 Cyclas (Nov. Spec). 
 
 Say Amer. Conchol. T. i. fig. 1. 
 
 T. i. fig. 2. 
 Rackett Linn Trans, vol. xiii. 
 Say Amer. Conchol. T. ii. fig. 2. 
 
 T. iii. fig. 3. 
 
 T. i. fig. 6. 
 
 Say Amer. Conchol. 
 
Dr Bia»BY on the Geographi/ and Geolo((i/ of Lake Huron 209 
 
 r- 
 ;r 
 e 
 1- 
 [)f 
 1- 
 it 
 J- 
 
 III. Account of an Explosion in a Vein of Pyrites. 
 
 This explosion took place, sixteen yearH ago. in the township of Yonge. 
 near the Lake of the Thousand Isles in the St. Lawrence At the lime, a 
 man was seeking his cow in the woods, within a short distance of the spot. 
 On a sudden he was startled by a tremendous explosion, attended by volumes 
 of smoke, and sulphurous odours. 
 
 Three years since, on being informed of these particulars. I visited the 
 place. It is half a mile within the woods north of the road from Brookvdie to 
 Kingston, near to the easternmost of two creeks, about ten miles from the 
 
 former town. 
 
 I found, on the summit of a quartzose mound from 30 to 40 teet high, a 
 round cavity, 12 feet deep, 12 long, and 9 broad. Its sides consisted ot very 
 shattered quartz spotted brown by oxide of iron, and covered profusely with 
 acicular yellow and white crystals of sulphur. The lower parts of the cavity 
 were studded with masses of iron pyrites, of which there is a vein at the bottom 
 of the cavity It is a foot and a half thick, and disseminates itself into the 
 surrounding quartz. This vein may be seen, running east with a very high 
 dip, to the distance of a yard and a half. , ., ^ 
 
 Similar phenomena have been noticed in a mountain in Vermont (vide Ame- 
 rican Journal of Science, for Feb. 1821), and in the country towards the head 
 of the Missouri (vide Travels of Captains Lewis and Clarke). 
 
 le 
 

 'U 
 
 Wi 
 
EXPLANATION OF THE PLATES. 
 
 PLATE XXV. 
 
 Fossif Orthocerae from Thessalon Island, Lake Huron : page 198. 
 
 The three figures in this plate (drawn of the natural size) belong to the same 
 species, and exhibit a remarkable structure in the siphuncle, which is large in 
 proportion to the size of the shell, and is dilated between each of the septa. It 
 contains within it a tube running throughout its whole length, diminishing 
 towards the lower end of the shell, and having radii in verticillations connected 
 with the sides between each enlarged portion of the siphuncle. 
 
 Fig. 1. shows the external form of the lower part of the shell ; and in the upper 
 portion, the siphuncle laid open, and the verticillated radii distinctly separate 
 from each other. 
 
 Fig. 2. represents the siphuncle laid open, but the radii have not been preserved in 
 this specimen. The interior tube diminishes irregularly towards the smaller 
 end, and seems to indicate that this part was formed of a substance which could 
 be dilated or contracted. This figure is drawn in an inverted position. 
 
 Fig. 3. represents the form and size of the shell and siphuncle, with its internal 
 tube. The radii are wanting in this specimen. 
 
 PLATE XXVL 
 
 Orthocerae from Lake Huron : page 196. 
 
 The figures in this plate exhibit varieties in the external form of fhe shells, 
 and of the form and proportionate size of the siphuncle. There is also great 
 difference in the size of the chambers as shown by the different distances between 
 the septa. These differences are sometimes considerable in the same specimen, 
 as in figs. 3 & 8. 
 
 PLATE XXVn. 
 
 Four views of the natural size, of a new species of Trilobite, named by Mr. Stokes, 
 Asaphus platycephalus, from St. Joseph's Island, Lake Huron : p. 199. 208. 
 
 Fig. I.fl. Upper view of the anterior pari, showing the position of the eyes, and the 
 lines of the sutures; which, as in all the species of this tribe, divide the shelly 
 crust at the eyes, and pass in a curved line near to the anterior margin ; at the 
 centre of this margin another suture joins the curved one, and passes round to 
 
 the under side. 
 l.b. Under view of the same. Fro n the centre of the anterior margin, the 
 straight suture above mentioned passes along the middle of this under side, till 
 it meets another suture, where a plate, of the peculiar form represented in the 
 fin-are, is attached. This plate of peculiar form has been detached at its suture 
 by compression. Its upper margin is rounded at each side, and its lower part 
 has a deep lumulated indentation, which was evidently the entrance into the 
 stomach. This is the part mentioned in page 208. 
 VOL. VI. * ^ 
 
 Fig. 
 
EXPLANATION OF THE PLATES. 
 
 Fi<r. I.e. Side view of the Hanie, showing the remarkably Hat form of the specimen, 
 " from which peculiarity the specific name has been taken. The shelly crust of 
 
 the under side joins the upper at the sides. This is usually the case with tri- 
 
 lobites in this anterior portion of the animal. 
 Fiif. 2. Posterior part of the same species. 
 
 PLATE XXVIH. 
 
 Fossil corals of the genus Huronia, from Drummond Island, Lake Huron. 
 These corals are described in page 202. 
 
 Huronia Bigsbei. 
 
 vertebralis. 
 turbinata. 
 • obliqua. 
 spheroidalis. 
 
 Fig. 1. 
 
 2. 
 
 3. 
 
 4. 
 
 5. 
 
 6. Section of H. vertebralis. 
 The generic character of these corals is thus described by Mr. Stokes, who has given 
 them the above names : 
 
 Polyparium stony, forming a straight jointed column of single cells placed 
 one over the other ; each joint having been in succession the habitation of the 
 livino- individual. The remarkable peculiarity which establishes these corals as 
 a particular genus is, that as a new generation arises, it forms its cell precisely 
 over the preceding one, covering its upper surface entirely, and lengthening the 
 column of the coral by a new joint in a continuous line with those previously 
 formed. 
 
 PLATE XXIX. 
 
 Fossil corals from Drummond Island, Lake Huron. 
 
 Figs. 1,2.0.2.6. represent a species of Caryophyllia, remarkable for the tubes 
 
 proceeding from it, as described in page 203. 
 Fig. 3. Very small species of Turbinolia. 
 
 Fig. 4. A species remarkable for the arrangement of the plates in the centre. 
 Fig. 5. Another species of Turbinolia. 
 Fig. 6. A species of Caryophyllia. 
 
 PLATE XXX. 
 
 Figs. 1 & 2. Two species of Orthocera, mentioned in page 204. 
 
 The other figures in this plate represent the columns of circular discs men- 
 tioned in page 204 ; but it has not yet been ascertained to what class of fossils 
 they belong. 
 
 PLATE XXXL 
 
 Map of Lake Huron. 
 
 For the authorities from which it is compiled, see p. 177 of this volume. 
 
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