* ' MARION ' ' EXPEDITION TO DAVIS STEAIT AND BAFFIN BA\' 69 



in the medium sand subdivision is shown in Table 5, column 6. A 

 scale of 1 to 3 is used : 1 indicates less than 5 per cent of the constit- 

 uents are frosted; 2, between 5 and 10 per cent; and 3, between 

 10 and 15 per cent. Except for samples 8 and 9, which are used 

 as standards and which contain about 15 per cent of polished grains, 

 the quantity of frosted components was estimated by inspection. As 

 this polishing occurs chiefly in the medium sands, the percentag-e of 

 frosted grains in the whole sediment may be estimated roughly from 

 column 5, Table 4, and column 6, Table 5. The maximum amount 

 of polishing occurs in sample 19 from the middle of Hudson Strait, 

 in which about 4 per cent of the sample consists of frosted sancl 

 grains. Most of the sediments contain 1 per cent. 



If one pilots on a map the relative frosting of the medium-grained 

 sands as shown in column 6, Table 5, he will see that the amount of 

 polishing tends to decrease toward the middle of Davis Strait ; sam- 

 ples 7, 15, 16, 22, and 27, all situated far from shore, contain rela- 

 tively few frosted grains. Sample 26 off Cape Farewell, on the 

 other side of the strait, similarly, is deficient in polished constituents. 



Descrvption of roch fragments. — The rock fragments range in size 

 from less than a millimeter to about 3 centimeters. Larger pebbles 

 probably occur, but presumably not to any great extent, from the 

 point of view of percentage composition of the sediments; because 

 large fragments are not common and most of the pebbles are less 

 than one-fourth inch (7 millimeters) in diameter. None of the 

 fragments are well rounded. Nearly all of them are faceted and 

 most of the edges of the facets are polished. The degree of round- 

 ing varies considerably, but the limestone pebbles are better rounded 

 than the others. 



The dominant rock types are gneiss, quartzite, and gray and buft 

 aphanitic noncrystalline limestone; hornblendite and various types 

 of granitic rocks are common ; basalt occurs sporadically ; and an 

 eroded pelecypod shell was found in one sample. Some of the frag- 

 ments classified as limestone probably are dolomite, as they effervesce 

 but slightly in cold hydrochloric acid. The distribution of the rock 

 types in the various sediments is summarized briefly in column 5, 

 Table 5, and on Figure 49. Gneiss or quartzite occurs in practically 

 ever}^ sample; except for the sediments off Cape Murchison, lime- 

 stone is almost universally present; hornblendite and granitic rocks 

 are less common, but their distribution is general ; basalt is restricted 

 to deposits south of Hudson Strait; and the pelecypod shell was 

 found in sample 24 off the north coast of Labrador. 



Cale.imii carhonate content.— The distribution of calcium carbonate 

 in the sediments is shown in Table 5 and on Figure 50. The fine- 

 grained deposits are fairly rich in CaCOs, most of them containing 

 from 20 to 40 per cent. The well-sorted sands off Cape Murchion have 

 less than 5 per cent and the distribution of CaCOs along the longi- 

 tudinal section off Cumberland Peninsula is variable. Samples 2 and 

 4 contain less than 5 per cent but adjacent samples have about 15 

 per cent. The Spearman coefficient of correlation, p,^ between the 



3 See R. E. Chaddock, Principles and Methods of Statistics, Houghton Mifflin Co., New- 

 York, pp. 300-305, 1925. 



