6o DISCOVERY REPORTS 



on some records where there is an indeterminate marking below the hnes. On the few that have remained 

 on the whole fairly legible there is no definite evidence of layering, although in one or two instances it 

 is just possible that this has been recorded. Our records, however, were very seldom taken in waters 

 as shallow as those previously mentioned; shallow water to us usually meant depths of 30 to i;o fm. 

 (55-91 m.), and even in enclosed anchorages in the Antarctic, where an overlay of glacial mud could 

 reasonably be expected, we were mostly compelled, from lack of accurate information, to anchor in 

 depths of water varying from 25 to 40 fm. (46-73 m.). In addition it must be remembered that our 

 supersonic transmitter and receiver tanks were mounted inside the hull plating, with a consequent loss 

 of signal strength. In the instance quoted above of the survey of Lake Windermere the transmitter 

 and receiver used were protected only by a thin sheet of metal ; for the other records shown in The 

 Husun Review nothing is known about the thickness of plating below the tanks. It is probable that 

 the face of the quartz transmitter referred to by Stocks was in contact with the sea, but even if it was 

 protected it is unlikely that such protection was more than a very small fraction of an inch in thickness. 

 The loss of records through fading may thus be serious, for they cannot now be subjected to a 

 critical examination. Such work can scarcely be done during a running survey, for the logging of 

 soundings, either direct from the recorder or from the dried paper after the day's work, leaves little 

 or no spare time. It is therefore to be hoped that as the result of the experiments now being made, 

 a more permanent marking on the records will be achieved in future. 



TERMINOLOGY OF SUBMARINE RELIEF 



The need for a systematic nomenclature for the features of the sea bottom became apparent many 

 years ago and the first serious attempt to provide for such a need appears to have been made by 

 Petermann, in 1877. Between then and 1899 Agassiz (1888), Murray (1895) and Supan (1899) 

 contributed greatly to the subject, and in the latter year, at the Seventh International Congress of 

 Geographers in Berlin, consideration was given to certain principles to be applied in naming the 

 features of the sea bottom. These principles were formulated by Kriimmel and Mill on a geographical 

 basis and have become the foundation of most of the modern nomenclature. In 1932 Littlehales 

 described the first and second magnitude forms of the ocean bottom together with an appropriate 

 terminology which had by then attained international currency. In the same year the International 

 Hydrographic Bureau published their Terminology of Submarine Relief. 



In 1936 an International Committee was formed to report on the 'Criteria and Nomenclature of 

 the Major Divisions of the Ocean Bottom ', and their findings were published by the Association 

 d'Oceanographie Physique (1940). The Committee considered many suggestions, but there is still 

 much confusion over some of the terms which should be applied to the relief of the ocean floor. 

 In the present report we have adhered generally to the terminology of Littlehales for the description 

 of the submarine relief, and for the nomenclature of the different divisions of the sea bed in the 

 southern seas to the terms hitherto generally adopted in the publications of the Discovery Committee. 

 Some of these terms were described by Mackintosh (1940) in his article for the International 

 Committee. We are not, however, altogether in agreement with the use of the term 'swell', which 

 now appears to be fairly widely used as the definition of a rise which separates two deep 

 basins, and which has a saddle depth of 4000 m. or more. The original word proposed by German 

 authorities to define such a feature of the bottom relief was ' Schwelle ', of which the literal translation 

 is 'siir, meaning a 'threshold'. It was to be additional to the terms 'ridge' and 'rise', which were 

 already well established. The use of the word ' swell ' as the alternative in English to ' Schwelle ' may 

 be intended to convey more accurately this conception of a slight rise or swelling of a few hundred 

 metres in the bottom relief at the greater depths, as opposed to a more definite rise of, say, 1000 m. 



