1854.] 



GEOLOGY OF WESTERN CxVNADA. 



51 



William sliells ave more plentiful, but not in great abundance, 

 while at Cape Croker and Cape JMontresor various species of 

 shells occur in great numbers, in addition to encrinites, corals 

 and fucoids. In the hard beds at the top of the formation, in 

 Owen's Sound, we met with numerous fossils ; they were prin- 

 cipally small shells and corals, and the forms having been re- 

 placed by silica, while the imbedding matrix is calcareous, they 

 were weathered out in relief on the exposed surfaces, being 

 precisely in the condition in which similar remains were found 

 in the upper beds of the same series last season, at Cabot's 

 Head and in the Grand Manitoulin Island.. The species of 

 Pterlnea (P. carinata) which appears to be peculiarly char- 

 acteristic of this series of rocks, is found more or less abundantly 

 in different parts throughout the Avhole vertical thickness, and 

 in great numbers at Point William, Cape Croker and Cape 

 Montresor. 



Concretionary nodules of calcareous quality, usually assuming 

 spheroidal or sub-spheroidal shapes, are thickly scattered through 

 the shales in some parts of the formation, and were observed 

 in particular among the, rocks in the neighbourhood of Cape 

 Boucher. 



The materials of economic importance observed associated 

 with the Jjoraine shales, were stones fit for building, for tiles 

 and flagging, with limestone and clay. For building, the hard 

 beds at the top of the series, are of tolerably good quality, when 

 the layers are not too thin, which however they frequently are, 

 and some of the calcareo-arenaceous bands might be used for a 

 rough description of tiles and flagging ; but the material is of 

 an inferior quality fbr either purpose.' There arc veiy few beds 

 fit for burning into lime ; an occasional one, however, is met 

 with among the blue and drab shales. When not too calcareous, 

 the clays derived from the disintegration of the shales constitute 

 material of good quality for brick making. Gypsum is reported 

 to have been found in the formation near Cape Commodore, 

 but the only specimens of it met with by me occurred in small 

 isolated masses of no economical importance, being such as are 

 known to exist in the formation elsewhere. 



IV. V. MEDINA SANDSTONE AND NIAGARA LIMESTONE. 



A bold precipitous escarpment marking the outcrop of the 

 Niagara limestones, was traced along the coast during the season 

 of 18-17, from Cabot's Head to Colpoy's Bay. Southward from 

 the bight of this bay, the escarpment leaves the coast, but main- 

 taining some degree of parrallelism with it, sweeps round to- 

 wards the heights over Cape Commodore, whence it runs nearly 

 due south, keeping two or three miles distant from the west 

 shore of Owen's Sound, until reaching the line between the 

 Townships of Derby and Sydenham, about three miles south of 

 the village of the latter name at tRe head of Owen's Sound, 

 where it strikes to the south-eastward and crosses the Owen's 

 Sound road. The subjacent formation was not exposed at any 

 part that we visited south of Colpoy's Bay, being concealed by 

 detritus and forest trees, but the soil at the base of the Niagara 

 escarpment was frequently observed to be of a rod color and 

 marly quality, leaving little doubt that it wa.s derived from the 

 immediately proximity of the marls of the Medina group. 



The upper part of the Niagara limestones, v/hich constitutes 

 tlic south shores of the Manitoulin Islands, strikes from Horse 

 or Fitzwilliam Island acro.ss to the Isle of Coves, then to Cape 

 Hard, whence it holds the coast and adjacent islands to Chief's 

 I'oint and the Riviere an Sable (north;) from this, striking 

 into the interior, it is no more seen on the hdcc. Rocks be- 

 linging either to the summit of tliis or to the base of the suc- 

 ceeding sunorinr (iirnintion were seen at (lalt, on the (!rand 



River, and beds belonging to the Niagara Group, were observed 

 occasionally coming to the surface, on the road between Gait 

 and L)uudas, but the. country north of Gait, and between it and 

 the mouth of the Rinere au Sable (north,) has not yet been ex- 

 amined, and I am unacquainted with the details of the geo- 

 graphical boundary of the summit of the formation in the in- 

 terval, which is nearly a hundred miles. 



Numerous fossils were observed in the Niagara limestones, 

 but the variety was not great except among the corals, which 

 were of many dift'erent species. The most characteristic shell 

 was a Pentamerus, which extended through the whole for- 

 mation, .but was most abundant near the top ; Euomplialus and 

 other spiral genera were luet with ; a large bivalve of a new 

 genus occurred in great numbers at Gait, associated with i-'eji- 

 tamei-us* Among the thin-bedded limestones at the base of 

 the formation (corresponding probably Avith the Clinton group 

 portion of it,) .some surfiices were thickly covered vrith organic 

 remains, an Alrypa and a small turbinated shell chiefly pre- 

 vailing. Trilobites, orthoceratites, corals and fucoids also, 

 though in less abundance, were observed in this portion, but 

 principally in one place near Cape Chin, on the south side ol 

 Dyer's Bay. 



The Niagara group is fruitful in excellent materials for build- 

 ing and lime burning. At Gait white limestone occurs of a 

 beautiful and enduring quality for architectural purposes, for 

 which it is extensively quarried from beds nearly horizontal, 

 varying from one to three feet thick, and blocks may be obtained 

 of almost any required size without much difiiculty ; the stone 

 burns also to an excellent lime. At Owen's Sound, about two 

 miles S. by E. from the village, there are unworked strata of 

 white or pale grey limestone ; the upper beds are from two to 

 four feet thick, the lower ones occasionally over twelve feet, 

 being all very massive ; the upper beds could be quaiTied to an 

 almost boundless extent, and would yield an excellent building 

 material ; the lower beds are likewise fit for building purposes, 

 but being the base of an abrupt escarpment could not be ex- 

 tensively quarried; large loose masses, however, skirt the es- 

 carpment, and these might be made available for a great length 

 of time. All the beds would stand the weather well ; many of 

 them have occasionally been burnt by the settlers, and are said 

 to make an excellent quality of lime. Materials of much the 

 same sort would be found all the way to Cabot's Head. On 

 the Riviere au Sable (north,) about a mile and a half or two 

 miles from its mouth, there are some pale greenish-blue lime- 

 stone beds, one of them darker than the rest, which woidd all 

 be fit for building purposes ; the stone appears to resist the dis- 

 integrating influences of the weather well, but it turns^ under 

 them to ablackish color. The beds are from eight to eighteen 

 inches, and even two feet thick ; they arc divided by parallel 

 joints into rhomboidal forms, and would afford blocks of any 

 "required size. At Chiefs' Point there is a limestone wliich 

 presents a white or pale gray color on fracture ; it has a rough 

 pitted exterior surface, and weathers to a dark tarown approach- 

 ing to Ijlack ; the beds are massive, ranging from two to tour 

 feet in thicknc.'is ; parallel joints intersect them, and they could 

 easily be quarried, and aflbrd a very substantial building stone : 

 most of the beds are supposed to bo fit for burning into lime. 



* Since Mr. Jlunay's examination of the rocks at Gait, Mr. Hall, of 

 New York, lias visiteil the spot, aiul in aJdition to the new bivalve, 

 ahovc mentioned, to whicli he projio.ses to give the name of Megulamua 

 Canrid'tisis, he lias met with other .shells, two of which ho recognises 

 as belonging to the Onondaga Salt Group, o»^ Gypsifcrous Limqstone, 

 and he is disposed to clas.s the Gait rocks with that formation.— 

 W. K, T-. 



