COMPARISON OF LAKE MELVILLE AND DOUBLE MER.
Professor Gregory urges that Lake Melville should be called a fiord because the adjacent Double Mer has been thus classed by me. His reasons (1 and 2) for classing thorn in the same category may be stated as similarity of origin. Lake Mjösen, in Norway, with an area of 140 square miles, and extending 1,080 feet below sea level, Professor Gregory would doubtless admit, has essentially the same origin as most of Norwegian fiords, yet no one calls it a fiord. Professor Gregory gives as the third reason why the Double Mer and Lake Melville should be classed alike that they “ are bounded by sub-parallel mountain walls.” But this cannot be admitted as true. Double Mer expands to a maximum width of 5 miles or less, while Lake Melville reaches a width of 25 miles or a little less. In the western part of Lake Melville basin the mountains retreat, leaving a wide terraced plain on both sides comparable with the lake itself in width. But the most significant and striking contrast between the two is seen in the fact that the long narrow approximately parallel-sided Double Mer receives, like other fiords, only the drainage of a trifling area, while Lake Melville transmits to the sea the drainage of an area equal to three-quarters of Great Britain. In other words, one is a fiord and the other is, with the Narrows, the terminal end of the largest river entering the Atlantic north of the St. Lawrence.
Even if Professor Gregory's claim that “ fiord valleys are independent of river action” were well founded, it would be useless to claim that the Lake Melville basin and the Narrows are not essentially a river valley in origin. Faulting was responsible for the old pre-glacial Hamilton river following the present valley, but the river was the essential active excavating tool which did most of its work when the continent stood many hundred feet higher than at present and when all of the Atlantic coast rivers emptied far to seaward of their present mouths. The approximate seaward extension of the Hamilton river in pre-glacial times is suggested in the supplementary sketch map attached to the accompanying copy of Spencer's chart1 showing the submarine river valleys of the north Atlantic coast.
Professor Gregory points out (page 11) that Lake Melville has a much greater tidal range than the Baltic, where it is less than 1 inch in places, and states that higher salinity is reported by Mr. Jones for Lake Melville than the northern part of the Baltic shows. It has apparently not occurred to him that the strong tidal currents of Lake Melville which are wanting in the Baltic because it is not part of a river system, together with the river current, result in a mixing of river and sea water in the lake which give, when compared with the fresh water end of the Baltic, relatively high salinity figures. Elsewhere in this Memorandum I have pointed out that a river current does in one case known to me entirely prevent thermal stratification of the water and that the salinity figure cited by Gregory is explained by the river current, which he overlooks, and the tidal currents together. Elsewhere
1 Plate 10, Hull's Mert, on the Sub-Oceanic Physiography of the N. Atlandtic ocean, 1912.
I have pointed out, however, the futility of comparing water bodies so entirely unlike in size as Lake Melville and the Baltic Sea, the latter having more than twenty times the breadth of the former.
The fragmentary character or trifling amount of data available concerning Lake Melville salinities make satisfactory comparison inpossible on any basis at present.
“ OBSERVATIONS ON THE FAUNA AND FLORA.”
BY C. TATE REGAN, M.A., F.R.S.,
Keeper of Zoology in the British Museum (Natural History).
Much of this memorandum is occupied with a criticism of my discussion of certain biological data contained in Memoir 141, Geological Survey of Canada.
I am willing to grant that it is sometimes difficult to draw hard and fast lines for the limits of a halophyte flora just as it is for a calciphile flora. But the fact that a particular species has been recorded both from seashore and the shores of inland lakes is not alone proof that such a plant may not be considered a halophyte. One or two of the most typical halophytes known to me have been found growing on the shores of Lake Winnipegosis near the middle of the continent and in the Slave river basin in highly alkaline and saline soils.
Professor Regan is so imbued with a belief in the high relative salinity of Lake Melville that he is disposed to believe that cod will yet be found in the lake. In view of the universal agreement of fishermen that they are entirely absent from this body of water such an opinion seems to be without foundation. The absence of the cod from waters which we are assured by Professor Regan have the proper salinity leads to the conclusion that either Professor Regan, or the cod, have made a mistake. I am not able to believe that the cod would overlook such a desirable habitat as Professor Regan suggests Lake Melville to be.
Ancylus lake, with its fresh water bivalves, the geological antecendent of the Baltic sea, probably represents a closer analogue to Lake Melville than the present Baltic sea with which Professor Regan compares it.
The great discrepancy in the size of Lake Melville and the Baltic sea should have deterred Professor Regan from his courageous attempt to predict the inaccuracies which the expects to be found in my Lake Melville report. The Lake is less than 100 miles long, with an average width of 15 miles or less, while the Baltic sea has a length of 960 miles and a maximum width of about 400 miles. The particular fallacy to which I wish to call attention resulting from the comparison of large and small bodies of water is associated with the thermal and other stratification of water bodies. In a large body
of water subject to sea waves like the Baltic summer thermal stratification will be quite different from that which will develop in a lake the size of Lake Melville. Two examples of lakes neat Ottawa will illustrate my meaning. A small lake (McKay) shows a July thermocline at 10 feet, the water above being near air temperature and below dropping abruptly to near freezing. Lake Deschenes, through which the Ottawa river flows, shows no thermocline in July, the temperature being nearly the same from top to bottom, a result of the current mixing the warm surface and cold bottom waters. In recent years naturalists have been learning to scrap their old ideas with reference to predicting from the biological conditions found in one body of water the conditions to be expected in another. B. W. Evermann, one of the keenest American ichthyologists has stated (see “ Lake Maxinkuckee, a physical and biogical survey ”) that the United States Bureau of Fisheries has wasted thousands of dollars by working on that theory in introducing fish into lakes where an intelligent examination of the local conditions would have shown the species introduced could not live. It is possible to take trout from a lake in which they thrive and drown them in a few minutes in the water of another fresh-water lake a mile away (see Birge and Juday, “ Inland Lakes of Wisconsin,” page 130). Yet the British Museum Zoologist undertakes, by comparing a brackish water Canadian lake with one of the great inland seas of Europe, to predict (page 8), that : “ It is not unlikely that cod may be found ” in the former. A comparison of the hydrography of the Baltic sea and Lake. Melville, in which certain alleged errors of the Canadian hydrographers are revised, as Professor Regan thinks they should be, led him to the extraordinary conclusion that the greater salinity of Lake Melville “ is very evident.” This conclusion is reached by comparing in diagramatic charts (pages 3-4) the salinity of Lake Melville as deduced from a limited number of water samples, none of which represent the river flood season, with the salinity of the Baltic based on several thousand samples and observations extending over a long term of years and including the four seasons of the year.
The exhaustive and elaborate character of the investigations of salinity and temperature conditions carried out by the Swedish and Danish Governments in the Baltic sea are sufficiently indicated by extracts from Peterson's account of them.1 “ The system adopted by the Swedish naturalists at the present time, in their exploration of the sea which surrounds the Scandinavian peninsula, is to despatch a number of ships simultaneously from different ports across that part of the sea which is to be explored, each ship being provided with a complete set of hydrographic instruments worked by assistants specially trained for their task in the laboratories of Stockholm's Hogskola, the Polytechnic Institute, etc. The route of each ship, and the position of every sounding station, are determined beforehand, according to previous experience.”
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“ In less than a week we collected at about seventy sounding stations
1 Scottish Geog. Mag. Vol. 10, pp. 281-282, 1894.
more than 1,000 water samples, and took the same number of temperature observations, besides 200 samples for gas analysis.”
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“ The hydrographic condition of the Baltic was minutely investigated in July, 1877, by a Swedish expedition, conducted by Professor F. L. Ekman, who collected about 1,800 records of temperature and salinity from different depths at sounding stations in all parts of the Baltic.”
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“ Four times a year, on the 1st February, May, August and November, thirteen hydrographic sections in different parts of the Kattegat and the Sounds are made by Danish gunboats.”
It should be noted that the Baltic figures of salinity represent the four quarters of the year, and any other figures compared with them, if reliable deductions are to result, must do the same. The Lake Melville figures used by Professor Regan, however, are based on samples taken in summer only, when the rivers are at their lowest stage. The important fact to note here is that the Lake Melville salinity figures entirely fail to cover the early spring period when the three-foot layer of ice melts and leaves a thick layer of quite fresh water which accumulates over much of the lake during the period when the ice prevents wave action and the consequent mixture with the brackish water below. These figures also fail to show the salinity of the lake during the flood period of late spring when the Hamilton, Kenimou and other large streams are emptying into Lake Melville the melted snow from their 60,750 square miles of drainage basin.1 It is the comparison of the Baltic salinity figures representing the four quarters of the year with Lake Melville salinity figures representing only one quarter, and that the summer period of minimum stage of rivers, which leads Professor Regan to his erroneous conclusion that Lake Melville is more saline than the Baltic sea. He might as reasonably take the temperature figures recorded for the Ottawa valley during July and August, and, ignoring winter figures, deduce from these the character of the climate of eastern Canada. This unfortunate comparison has even led him to question some of my carefully established facts which are recorded in map form concerning the distribution of two typical marine animals (figure 6, page 52, Memoir 141, Geol. Surv. Can.). Professor Regan in questioning the accuracy of this map on the basis of a salinity of Lake Melville claimed to be greater than that of the Baltic overlooked the fact that his information regarding the salinity of Lake Melville during the freshet season was equivalent to zero. Biological predictions based on that sort of data need no discussion. Without
1 The contrast between the summer-autumn as compared with the winter-spring salinity of the terminal portions of many N. American rivers is widely recognized in the eastern United States as the following quotation will suggest :
“ The oyster fishery in Mississippi is prosecuted in Mississippi Sound. The absence of oysters in the rivers may he due to the fact that, while the waters are brackish a distance of 5 to 10 miles up from the river mouths from June to November, they are practically fresh the remainder of the year.” (U.S. Commission of Fish and Fisheries ; Report of Commissioner, Pt. 29, 1905, p. 454.)
having been closer to the problem he is writing about than the opposite side of the Atlantic, Professor Regan states, speaking of Littorina, that “ further investigation may be expected to reveal its widespread occurrence west of the Narrows wherever there are shores suitable for it,” and finds the distribution recorded by me difficult to believe. My results are plainly shown as regards the intertidal zone by the map (page 52), which indicates abrupt termination of the Littorina marine tidal zone fauna at the entrance to the lake. ] began the study of the estuarine distribution of marine animals more than ten years ago (see Amer. Jour. Sci., May, 1916, pp. 449-461), and gave the most careful attention to gathering the facts for the map in question because of my general interest in the control exercised by fresh and brackish water over the upstream range of marine shells. In the present case the facts were secured by cruising near the whole of the north and south shores of Lake Melville with the aid of a small launch and canoe. The rocky shores, which are essential for the abundant occurrence of Littorina and Balanus balanus, are nearly everywhere present, but these shells are absent. Only one conclusion is possible in the face of these carefully established facts of distribution concerning Professor Regan's claim for a salinity of Lake Melville comparable with the Baltic sea. It is entirely unwarranted. The marine intertidal fauna fails to extend west of the Narrows because of the fresh and brackish water which they everywhere encounter to the westward. Within the Narrows the violent currents mix so completely the fresh water with sea water that the salt water fauna suffers no great harm.
In his conclusion Professor Regan states that the “ most striking feature of my report is the absence of any positive evidence as to the character of the fauna and flora of the Hamilton inlet west of the Narrows.” I am glad he has called attention to this feature of the report. If he will examine the literature on the Pleistocene deposits of the Upper St. Lawrence and Lake Ontario valley he will find it displays the same “ striking feature ” for the region west of Brockville, which he has noted in my report, while below Brockville marine fossils from numerous localities are recorded. The reason for this is that during the Pleistocene submergence of the St. Lawrence valley brackish water conditions prevailed along the head of the present St. Lawrence and Lower Lake Ontario valley, which suited neither marine nor fresh water faunas, and no organic remains representing the shore deposits of this time have ever been found between Brockville and Lake Ontario. For the same reason there is little to record concerning the intertidal zone of Lake Melville. Fresh water shells may be carried down to it from the rivers at times, but I saw none.