SOIL SURVEY

-10-differences among the till materials are not as evident as the range of exposed stratigraphicunits would suggest they might be . Observations made during the course ofthe soils inventory indicate that the majority of the glacial deposits found in Yohoare derived from limestones and shales . In the Eastern Facies, the mixture is dominatedby carbonate rocks, while in the Western Facies, the mixture is dominated b yargillaceous rocks, but in either case, the result is usually a medium textured ,calcareous material . Exceptions to this are the glaciofluvial deposits which ar ecoarse textured, reflecting their mode of deposition and some of the glacial til ldeposits which are discussed below .It was observed during the course of the soils inventory that the till deposit sin the vicinity of quartzite exposures are coarse textured and non-calcareous, resultin gin the soils characteristic of the Lake O'Hara area . Till deposits which are furthe rnorth of the Lake O'Hara area are finer and more calcareous as a result of admixtur ewith limestone and shale materials over which the ice has passed . These observation sare in agreement with work by Fox (1974) which indicates that the majority of th etill deposits in the Cataract Brook area are the result of two of the four separate ic eadvances which he recognizes . The first of these two, which Fox named the Earl yIntermediate, was fairly thick and deposited till along the whole length of th eCataract Brook valley . The second advance, which Fox named the Late Intermediate ,was thinner and left localized till deposits . Observations made during the soil sinventory indicate that the Early Intermediate Advance mixed Gog Group material swith other stratigraphic materials which gave rise to the till which is characteristi cof the Cataract Brook Valley, while an area of ice associated with the Late Intermediateadvance would only have been in contact with the Gog Group and thus lef tthe coarser till deposits, characteristic of the Lake O'Hara area .The till deposits associated with the hornfels unit in the Porcupine Cree kvalley, are also coarser and less calcareous than the till deposits which are typica lof Yoho .