CANADIAN PLEISTOCENE FLORA AND FAUNA. 329 



a period of erosion, during which the floor of Hudson River shale was cut 

 down more than 16 feet, preceded the deposit of the lowest warm climate 

 beds. This, with the downward extension of the interglacial beds, as 

 described in previous reports, for at least 15 feet, lengthens the time 

 necessary for the interglacial episode considerably. 



The new deposits in the western part of the city are exposed partly 

 in cuttings for sewers, but chiefly in two large sandpits, now worked 

 energetically because of the increase of building operations in Toronto. 

 These exposures lie from three to four miles west of the Don and are 

 either interglacial or preglacial, since more or less boulder clay overlies 

 them, though wave-action on the old Iroquois shore, 160 feet above the 

 present Lake Ontario, has removed part of the overlying till. 



Sections at the sandpits near Christie and Shaw Streets show 

 30 to 40 feet of sand and gravel tumultuously cross-bedded, as if formed 

 in a rapidly flowing river or near the shore of a large lake. The upper 

 part of the stratified sand is often contorted and broken into irregular 

 masses immediately under the till. The more gravelly layers contain a 

 few shells, c\n.QQ.j Campelomadecisa, Valvata sincera, species of Pleurocera 

 and Sphaerium, and occasionally fragments of unios. A few mammalian 

 remains have occurred also, fragments of a tusk of mammoth or mastodon, 

 and an atlas vertebra of an animal not smaller than an ox, having been 

 found within the past year. The latter bone could not be determined by 

 comparison with the skeletons at hand in the Biological Museum of 

 Toronto University, and so was sent by Mr. Archibald Pride of the 

 Biological Museum, to whom it had been referred, to his brother in 

 Dublin. There it was considered to belong probably to Bison americanus. 

 Toronto is the most easterly locality in Canada where remains of this 

 inhabitant of the prairies have been found. 



As these stratified sands differ greatly from any of the interglacial beds 

 of the Don or Scarborough, though underlying apparently the same sheet 

 of till, it seemed possible that they were preglacial. To settle this point it 

 was decided to sink a well to bed rock from the bottom of the Christie Street 

 sandpit, using the grant of 10/. to the Committee for this purpose. As the 

 sand below the bottom of the pits is heavily charged with water, it was 

 necessary to drill the well and sink a pipe as the work progressed. After 

 thirty-eight feet of rather uniform sand had been penetrated, a layer of 

 cemented gravel or conglomerate put an end to the work with the appliances 

 employed. 



Another well was sunk half a mile to the south, near a stream which 

 had cut through forty feet of till. Here the drill reached the underlying 

 Hudson River shale, giving a complete section of the drift, as follows : 



ft. in. ft. in. 



Till, blue clay with a few scratched stones . . iO 99 



Fine and coarse grey sand 14 59 



Clay without stones 9 3 45 



Gravel Goosely cemented) 2 6 35 9 



Clay without stones 2 9 33 3 



Sand and gravel 13 6 30 6 



Hudson Eiver Shale 17 



Level of Lake Ontario 



As no boulder clay was found beneath the sand, the question remained 

 undecided whether the beds are interglacial or preglacial ; but the open- 

 ing of a sewer on Dupont Street, half a mile north-east of the sandpits, has 



