Nov. 23, 1888.] 



SCIENTIFIC NEWS. 



539 



In an Appendix some igneous rocks found in the Bos- 

 worth borings were described. 



The President referred to the derivation of the mate- 

 rials of the Permian breccia as an important instance of 

 results due to investigation by local students, and the 

 light thereby thrown on ancient physiography. He was 

 sceptical as to the lacustrine origin of these breccias. 

 Why not subaerial, like those in the interior of Asia ? 

 — subangular masses, transported by rainwash to a dis- 

 tance of 10 or 12 miles. 



Professor Bonney agreed as to the existence of a bar- 

 rier of land linking the old area of Warwickshire with 

 Charnwood, and that the breccias did not obtain materials 

 from the Lickey, the east side of which he believed to 

 have been partly covered by coal-measures at that period. 

 The specimens were not exactly of the Hartshill type, 

 and he was prepared to believe that they came from a 

 ridge now no longer visible. He thought, from the nature 

 of the cleavages in the older rocks of Charnwood, that 

 there must have been pre-Carboniferous movements also 

 in that district. 



Mr. Whitaker said it was unreasonable to suppose that 

 Conglomerates should always have been derived from 

 exposures now visible. Therefore the alleged under- 

 ground extensions may easily have furnished these 

 materials. Were the Charnwood rocks of fairly inde- 

 structible material ? 



Professor Blake agreed as to the relations between 

 these beds and the Carboniferous. Was the Permian age 

 so very distinct from that of the Trias ? Mr. Wilson 

 regarded the Permian and Trias as really one physical 

 sequence. Are they, then, really separated by such a 

 wide gap ? He commented on the appearances at the 

 Swadlincote section. Why might not these Permian 

 beds represent the base of a new epoch ? The stones in 

 the deposits on the eastern side were quite different. 

 When the Trias escapes from the Permian it becomes 

 irregular. Were the Coal-basins separated by the Per- 

 mian movements ? If so, the materials dispersed should 

 form the base of the Permian. Is there evidence that 

 these beds belong to a distinct epoch from the Trias, and 

 are not merely its base ? 



Mr. Topley observed that the main point of the paper 

 was the relation of the beds called Permian to those 

 above and below. The author had well traced out the 

 underground ridge, but what is the evidence of its being 

 a faulted anticlinal ? 



The Author, in reply, stated that he was not prepared 

 to uphold the lacustrine origin of the breccia ; but if 

 subaerial it would make no difference to his argument. 

 With regard to the age of the Charnwood anticlinal, the 

 post-carboniferous movements took place along old lines 

 of disturbance. The scarcity of Charnwood rocks he 

 thought due to the drift having been from the south, and 

 this would help to account for their exceptional abundance 

 at Hartshorn. He had originally been prejudiced in 

 favour of the Permian being the base of the Trias, but 

 found the theory untenable. The material was different 

 from that of the Eastern Permians, and from the material 

 which makes up the basement breccia of the Keuper at 

 Castle Donnington. The maximum angularity of the 

 breccia in the southern part of the area was another point 

 in favour of its derivation from a southern source. As 

 regards evidence of a faulted anticlinal in the subtriassic 

 ridge, the shales were found to be in a smashed con- 

 dition, and instead of coming to quartzites below, 

 something altogether different was found — appearances 



which could only be explained on the supposition of 

 faulting. 



On the Supeificial Geology of the Central Plateau of 

 North-Western Canada. By J. B. Tyrrell, Esq., B.A. 



The drift-covered prairie extends from the west side 

 of the Lake of the Woods to the region at the foot of the 

 Rocky Mountains, rising from a height of 800 feet on the 

 east to 4,500 feet on the west, the gentle slope being 

 broken by two sharp inclines known as the Pembina 

 Escarpment and the Missouric Coteau, giving rise to the 

 First, Second, and Third Prairie Steppes. 



The Author described the older rocks of this region, 

 referring especially to his subdivision of the Laramie 

 Formation into an Edmonton Series of Cretaceous age, 

 and a Pascapoo Series forming the base of the Eocene, 

 and then discussed the Superficial Deposits in the fol- 

 lowing order : — 



1 . Preglacial gravels occurring along the foot of the 

 Rocky Mountains, composed of waterworn quartzite 

 pebbles. 



2. Boulder-clay or Till, having an average thickness of 

 50 to 100 feet, and filling up pre-existing inequalities. 

 The clay is essentially derived from the material of the 

 underlying rocks. The smoothed and striated boulders 

 of the western region are largely quartzites derived 

 from the Rocky Mountains ; these gradually disappear 

 towards the east, and are replaced by gneisses and other 

 rocks transported from the east and north-west. Some 

 of the surface erratics of gneissose rock have doubtless 

 been derived from the Till, whilst others are connected 

 with moraine deposits, and others, again, appear to have 

 been dropped from bergs floating in seas along the ice- 

 front. The Till is sometimes divisible into a lower 

 massive and upper rather stratified deposit, separated 

 occasionally by 



3. Interglacial Deposits of stratified? material, with 

 seams of impure lignite, and shells of Pisidium, Li/uncea, 

 Planorbis, etc. 



4. Moraines, which are intimately associated with the 

 Boulder-clay, and represent terminal moraines of ancient 

 glaciers which originated upon or crossed the Archaean 

 belt. One of these is the well-known Missouric Coteau. 



5. The Karnes or Asar generally occurring at the 

 bottoms of wide valleys, and which resemble in structure 

 those of Scandinavia. 



6. Stratified Deposits and Beach-ridges which have 

 been formed at the bottoms and along the margins of 

 fresh water lakes lying along the foot of the ice-sheet. 

 The principal of these occupied the valley of the Red 

 River, and has been called Lake Agassiz ; it had a length 

 of 600 miles and a width of 170 miles. 



7. Old Drainage-channels. — Throughout the whole 

 region old drainage-channels appear to have been occu- 

 pied by southerly running rivers (where the present 

 drainage is northerly), and are considered to have carried 

 away the waters draining from the foot of the ice. 



The President spoke of the interest of studying these 

 American deposits. The determination of the age of the 

 Laramie beds by no means did away with the interesting 

 fact of the interstratification of beds containing Tertiary 

 plants with others holding Cretaceous reptiles. 



Dr. Hinde remarked that the opinion was formerly 

 held by some Canadian geologists that many of the 

 superficial deposits were produced by marine Arctic 

 currents in a period of depression. 



Mr. Topley referred to the rich alluvial deposit filling 



