50 



GEOLOUY OF WESTERN CANADA. 



[1854. 



settleibeiits first appear a short distance to tlie south of Point 

 Clark, the fore.st being here and there indented with extensive 

 clearings which increase in size and number, approaching 

 Goderich. South from Goderich the principal settlement we 

 observed was at Bayfield River, but the rest of the coast between 

 that river and Port Sarnia, on the St. Clair, is as yet but thiidy 

 peopled. Kettle Point and the neighbourhood are still, I un- 

 derstand, in the possession of the Indians, and are in con- 

 sequence but little cultivated. 



With the exception of Goderich harbour, at the mouth of 

 the Maitland River, and the basin at the exit of Riviere au 

 Sable (south,) there is not a single place of security for any 

 description of vessel between the River Sauguine and the St. 

 Clair. Small boats, I was informed, could enter Big Pine 

 Brook, but no craft of larger size. There are no islands, no 

 coves, no accessible brooks or streams, and with strong v/iads 

 from the south, west or north, it is difficult, if- not impossible, 

 to land boats with safety. At many points the water is very 

 shallow and large boulders often lie at a long distance out in 

 the lake, while a very heavy sea breaks every where along the 

 coast. 



Distribution of the Rock Formations. 

 The rocks exhibited upon that part of Lake Huron now 

 under consideration, are portions of the whole suite of fos- 

 siliferous deposits between the Trenton Limestone (using the 

 New York nomenclature,) at the base, and the Haujiltou Group 

 at the summit, both inclusive ; the superposition, in ascending 

 order, being as follows : 



1. Trenton Limestone, 



2. Utica Slate, 



3. Loraine Shales, 



4. Medina Siindstone and Marl, 



5. Niagara Limestone, 



6. Onondaga Salt Group, or Gypsiferous Limestone and Shale, 



7. Corniferous Limestone, 



8. Hamilton Group. 



I. TRENTON LIIIESTONS. 



As already remarked in former Reports, the Trenton Lime- 

 stone occupies the whole of the Peninsula between Matchedash 

 and Nottawasaga Bays, and the group of islands lying off its 

 extremity, consisting of the Giant's Tomb, Hope, Beckwith and 

 Christian Islands. At the head of Matchedash Bay, near the 

 entrance of the Cold Water River, the limestones are found ' 

 with a narrow band of green sandstone below them, resting un- 

 conformably upon gTieiss, and from that spot a nearly straight 

 line drawn down the Bay to the Giant's Tomb, would mark the 

 lower boundary of the formation, the limestone being seen out- 

 cropping at intervals on the south west shore, while the islands' 

 and mainland on the opposite side display nothing but the 

 older rock in its various granitic and syenitio aspects. The 

 upper members of the Trenton formation were found about 

 eight miles west from Nottawasaga River at MoGlashan's Mills, 

 at Hurontario in the Township of Nottawasaga, at the little 

 islands, called the Hen and Chickens, and on the coast in the 

 iST.W. corner of the Township of Nottawasaga, where they were 

 seen to pass below the Utica slate. The tranverse breadth of the 

 formation is thus about thirty miles, and its thickness, suppos- 

 ing the dip to be to the south-westward at the rate of thirty feet in 

 a mile, would be 900 feet. But it is not unlikely that it may 

 be affected by very gentle undulations and it would therefore 

 be scarcely safe to state the probable amount at more than 600 

 to 700 feet. The arenaceous portion of the formation, distin- 

 guished by the New York geologists as the Calciferous sand- 

 rock, is usually found at the base, and beds more or less sili- 



cious occur at intervals throughout the whole thickness. Green 

 calcareous and argillaceous shales are also frequently met with, 

 usually holding numerous fossils, and alternating with beds of 

 good limestone ; the pure limestones are sometimes of a buff 

 color and very fine texture, in which case fossils are scarce, 

 those in such instances most prevalent, being small fucoids 

 generally replaced by calcareous spar, running through the beds 

 vertically to the plane of stratification. Other beds are gray in 

 color, granular and crowded with fossils. Among these beds 

 some hold the tail of a trilobite (^Isotdns gigas) in great 

 abundance, while others are almost exclusively composed of the 

 remains of a species of Laptana. The fossils obseiTed to prevail 

 throughout the formation were several species of Leptena, 

 Cijpricardi.a, several spiral univalves, orthoceratites, trilobites, 

 chiefly Isotelus gigas, encrinites, corals and fucoids. 



In the variations in mineral quality in different parts of the 

 formation, some beds are so very arenaceous and hard as to be 

 altogether unfit for burning into lime, or where not too sUicious 

 for such a purpose, the lime assumes when slacked such a dark 

 yellow color as to unfit it for white-washing, while it permits 

 but a small admixture of sand in forming mortar. Other beds 

 on the contrary are uncommonly free from silicious matter, and 

 are then often bituminous, and sometimes have a slightly argil- 

 laceous aspect. The lime from these beds is of excellent 

 quality. 



II. TJTICA SLATE. 



Black bituminous shales come to the surface on the coast of 

 Nottawasaga Bay, in the fourth concession of Collingwood, with 

 beds of close-grained, dark-brown bituminous limestone inter- 

 stratified. The limestones contain fossils, but by no means in 

 such abundance as the shales, which are uncommonly pro- 

 ductive, the prevailing fossil being the tail of the Isotelus gigas, 

 which greatly predominates, but is accompanied by Triarthtis 

 hcckii, Orthis, Lingula, Ortlwceras and GraptoHthus. 

 III. _ LOEAINE SHALES. 



The first exposure of the formation we met with on our route 

 along the coast was near Cape Boucher, in Nottawasaga Bay, 

 where cliffs rising abruptly to the height of 150 feet, present 

 sections of buff or drab-colored argillaceous shales, interstratified 

 with thin beds of gray yellow-weathering sandstone. It next 

 makes its appearance at Point Rich, and continues exposed, in 

 - a high nearly vertical cliff, thence to Point William, where we 

 found blue and drab-colored argillaceous shales, with thin alter- 

 nations of calcareous sandstone and thin beds of limestone. 

 The upper part of the formation was observed in a cliff about 

 100 feet high at the head of Owen's Sound, immediately over 

 the steam-boat wharf, where the base of the precipice displayed 

 shales of a similar character to those at Point William, which 

 were overlaid by hard beds of gray or brownish yellow- 

 weathering silicious limestone capping the summit. Portions 

 of the formation are seen at Cape Commodore, on the islands 

 opposite to Colpoy's Bay, at Cape Croker, and other parts of 

 the coast, until reaching Cabot's Head, where they were ob- 

 served to pass below the Medina rocks, as noticed in the Repoi-t 

 of last year. If a straight line were drawn from Point Rich to 

 Cape Croker, to represent the outcrop of the base, the formation 

 would have a breadth of about twenty miles at Owen's Sound, 

 which, at the supposed slope of thirty feet in a mile, would give 

 a thickness of about 600 feet. 



Fossils are found in vast abundance, but unequally distributed 

 through the formation. In the section near Cape Boucher they 

 consist chiefly of stems of encrinites and pentacrinites and also 

 fucoids, shells of all kinds being very scarce. At Point 



