ROCKS EXAMINED ON AUGUST 9TH. In the afternoon of the ninth of August, interesting outcrops of PreCambrian rocks within a radius of about a mile of the village of Madoc were studied. The members were supplied with a detailed map of the area on a scale of 1,000 feet to the inch published by the Ontario Bureau of Mines. Immediately north of the village fragmental rocks of complex origin were examined and found to consist (1) partly of a felsite intrusion holding very numerous fragments of other rocks, including crystalline limestone, (2) partly of agglomerate, and (3) partly of crush-breccia. About a third of a mile to the northeast of the Catholic church, beds of 'conglomerate" (Fig. 2), slate and limestone were examined. The pebbles of most of this "conglomerate" consist of crystalline limestone, and some of FIG. 2.-Limestone conglomerate, beds 2 and 4, interbedded with slate. the excursionists thought that it was a crush-conglomerate formed by the brecciation of the crystalline limestone. The majority, however, considered that it was a true water-worn conglomerate, interbedded with slate and limestone. The excursionists then went west to the Hastings road, along which they walked northerly about a mile, over steeply dipping beds of crystalline limestone, slate and other fragmental rocks, and visited an abandoned slate quarry. From there they proceeded west to lot 4 in the fifth concession of Madoc township, walking over an amygdaloidal andesite, to examine beds. of "conglomerate" (Fig. 3), which are here interstratified with slate. Most of the pebbles of this "conglomerate" are crystalline limestone, the rock being somewhat similar to that mentioned in the preceding paragraph. The majority of the party was inclined to consider the "conglomerate" a true water-worn type, while others thought it was of the nature of a crush-breccia. The slate, however, with which the "conglomerate" is interbedded, is only very slightly brecciated; and it was pointed out that, if the conglomerate was formed by crushing of the limestone, the slate ought to be also crushed and brecciated. It was noted also that the "conglomerate" contains also a 12-inch bed of quartzite which shows no evidence of brecciation. On the other hand, it could be seen that the limestone "conglomerate" passes into massive crystalline limestone, which was considered by some of the party as evidence that the rock is a crush-conglomerate. The latter rests on an amygdaloidal andesite, the plane of contact dipping about 37° to the southeast. The contact is exceptionally well FIG. 3.-Limestone conglomerate? lot 4 concession five, Madoc township, exposed, and most of the members of the party considered that the "conglomerate" lies unconformably on the andesite. ROCKS EXAMINED ON AUGUST 10TH. The party left the village of Madoc in six automobiles on the morning of August 10 and travelled about 45 miles in a northeasterly direction across the counties of Hastings, Addington and Frontenac. Each member was given a geological map on a scale of one-half mile to an inch, published by the Ontario Bureau of Mines, which embraced the area traversed. The route passed over Pre-Cambrian rocks of the Keewatin, Grenville, Laurentian, Hastings and post-Hastings series, and afforded opportunities for observing these ancient rocks. The first point examined is about three and a half miles east of Madoc, at the northwest corner of lot 2 in the second concession of the township of Madoc, where an excellent exposure of schistose Hastings conglomerate occurs. The pebbles, which show considerable variety, consist in part of crystalline limestone, proving the existence of an unconformity between the crystalline limestone, which occurs in large volume a few hundred yards to the south, and the Hastings conglomerate. The base of the Grenville series was next examined. The point where this is well exposed lies about a mile northeast of the village of Actinolite, in the township of Elzevir. There occur hornblende-schists of the Keewatin on which rest quartzites and greywackes now altered to quartz-mica-schists and resembling the Coutchiching of northwestern Ontario. The latter pass upward into crystalline limestone, the whole series of quartz-mica-schists FIG. 4.-Pillow lava, Keewatin series, Barrie township, southeastern Ontario. These lavas are generally altered to amphibolites and green schists, but in this area the ellipsoidal structure is well preserved. and limestone having a thickness, on this cross-section, of about 1,100 feet measured across the schistosity. The contact between the quartz-mica-schist and Keewatin hornblende-schists is such as to indicate that the Grenville. sediments were depsoited on the surface of the Keewatin lavas without erosion of the latter. The party then proceeded to Bishop Corners, Barrie township, Frontenac county, passing over extensive areas of Laurentian granite-gneiss, and also of Keewatin greenstones and Hastings conglomerate in less volume. About half a mile south of Bishop Corners, lot 3, Addington road, Anglesea township, in a field a few hundred yards east of the Addington road, is an excellent exposure of the Hastings conglomerate containing, among other fragments, pebbles of quartzite, banded chert, white quartz, quartz-porphyry and crystalline limestone. It was remarked by some of the members of the party that the rock resembles certain facies of the Lower Huronian conglomerate of the Lake Superior region. The base of this conglomerate may be seen resting unconformably on the Keewatin hornblende-schists less than a hundred yards west of the Addington road, where the basal member may be observed to consist largely of fragments of the adjacent Keewatin greenstone-schist. About half a mile north of Bishop Corners, on lot 8, Addington road, Barrie township, and to the east of the Addington road a short distance, there occur low hills of pillow lavas of the Keewatin series (Fig. 4). These can be traced gradually into hornblende-schists, or amphibolites, proving conclusively the igneous origin of the green schists. The pillow lavas in which the ellipsoidal structure may be clearly recognized have an areal extent in this vicinity of two or three square miles. After examining this outcrop the members of the party proceeded to Bon Echo Inn, Mazinaw lake, several miles to the north, where luncheon was served. They then went to the southern part of the township of Barrie to examine a contact of the Hastings conglomerate and a quartzite of the Grenville series. The nature of the contact, which is well shown on lot 24 in the first concession of the township, aroused discussion, it being held by some members that the relationship between the conglomerate and quartzite is a conformable one, while others considered that an unconformity is clearly shown by the fact that the conglomerate contains many pebbles of the quartzite. This being the last point to be examined, the party left for Madoc, where they arrived about 8 o'clock the same evening. Toronto was reached the following morning. CYRIL W KNIGHT. Excursion CI. TRANSCONTINENTAL VIA CANADIAN PACIFIC RAILWAY AND CANADIAN NORTHERN RAILWAY. AUGUST 4TH SEPTEMBER 6TH. Leader: F. D. ADAMS. Associate leader: J. B. TYRRELL. Secretary: J. McLEISH. Assistant secretary: H. S. DE SCHMID. Guides: J. A. ALLAN, Calgary to Kamloops, August 20-25. A. E. BARLOW, Coldwell, Banff to Golden, Sudbury, August 15, 20, 23, September 5. C. H. CLAPP, Victoria, August 26-27. W. H. COLLINS, Iron Spur to Fort Frances, August 16-17. R. A. DALY, Banff to Vancouver, August 20-25. C. W. DRYSDALE, Sicamous to Vancouver, August 25. J. C. GWILLIM, Bankhead to Calgary, August 20, August 30. E. M. KINDLE, Stonewall, Stony Mountain, August 18. A. MACLEAN, Stony Mountain, Stonewall and Snake Island, August 18, September 1. A. L. PARSONS, Kenora, Port Arthur, Loon Lake, September 2-3. S. J. SCHOFIELD, Victoria, August 26. W. J. SUTTON, Victoria, August 26-27. W. L. UGLOW, Iron Spur to Fort Frances, August 16-17. C. D. WALCOTT, Field, August 22. R. C. WALLACE, Stony Mountain, Stonewall and Snake Island, M. E. WILSON, Iron Spur to Fort Frances, August 16-17. |